General, Technical Data - HVAC: Other Volkswagen Eos I

A/C SYSTEM AND REFRIGERANT R134A, SAFETY PRECAUTIONS

1. Do not attempt repair on filled air conditioning systems by soldering, brazing or welding. This applies also for welding and soldering work on the vehicle, in the event that parts of the A/C system may heat up. When performing paint work repairs, the temperature in the drying booth or preheating zone must not exceed 80°C (176°F).

Reason

Exposure to heat increases the pressure in the system, which could cause the pressure relief valve to open.

Corrective action

Discharge refrigerant circuit using service station.

Note. Always replace damaged or leaking A/C system components. Do not attempt to repair them by soldering, brazing or welding.

Refrigerant vessels (such as, charging cylinders of A/C service station) must never be subjected to excessive heat or exposed to direct sunlight.

Corrective action

Vessels must never be completely filled with liquid refrigerant. Without sufficient room for expansion (gas cushion), vessels will rupture with devastating effect in the event of an increase in temperature. Refer to REFRIGERANT R134A CHARACTERISTICS .

Refrigerant is never to be transferred to systems or vessels in which air is present.

Corrective action

Evacuate systems and vessels before charging with refrigerant.

A/C SYSTEM, REPAIR INFORMATION

1. An A/C system made for refrigerant R12 must not be filled with refrigerant R134a without making modifications to the refrigerant circuit. Refer to «REFRIGERANT CIRCUIT, CONVERTING R12 TO R134A AND SERVICING»(ref-475566-S08002425572012052300000) .
2. The refrigerant oils specifically developed for R134a and R12 refrigerant circuits are never to be mixed.
3. Service stations which come in contact with the refrigerant are only to be used for the intended refrigerant.
4. Components of R134a refrigerant circuits can be identified by their markings, green labels or design (such as different threads) to prevent interchanging with components designed for refrigerant R12.
5. A label indicating the refrigerant used is provided in the engine compartment on the lock carrier or in the plenum chamber.
6. Different refrigerants are never to be mixed.

Note. When working on the refrigerant circuit, always heed the information given in A/C SYSTEM AND REFRIGERANT R134A, SAFETY PRECAUTIONS and REFRIGERANT CIRCUIT, GENERAL PRECAUTIONS .

Special Tools and Accessories

The performance of proper workmanlike repairs on an air conditioning system

1. Requires the use of special tools and materials as listed in «SPECIAL TOOLS»(ref-475566-S30117863212012052300000) .

1. Requires compliance with the basic instructions for use of leak detectors. Refer to «REFRIGERANT CIRCUIT, FINDING LEAKS WITH ELECTRONIC LEAK DETECTOR VAG 1796»(ref-475566-S37050865692012052300000) .

1. Requires expert knowledge.

Note. Releasing refrigerant into the environment is not permitted (punishable by law). Refer to LAWS AND REGULATIONS .

A/C SERVICE AND RECYCLING UNITS

At this time, A/C service units for extracting, cleaning and filling refrigerant for motor vehicle A/C systems are available from various manufacturers.

EVAPORATOR, SPRAYING WITH PRESSURE CUP GUN AND SPRAY NOZZLE VAG 1538

Spray off the evaporator directly with Contra Sept using a spray nozzle (approximately 10 bar) Contra Sept neutralizes microbes and bacteria directly on the evaporator.

To make it possible to access the evaporator, some prework and different spray nozzles are needed, for example -V.A.G 1538/5-; -V.A.G 1538/6- or -V.A.G 1538/7-.

A vehicle-specific instruction booklet is included with the evaporator cleaning solution -D 600 100 A2

For the current units and spray nozzles, refer to Service Net.

EXTRACTION AND CHARGING SYSTEM SAFETY PRECAUTIONS

1. Make sure the shut-off valves are closed before connecting the charging system to the air conditioning system.
2. Make sure the process is finished before disconnecting the charging system from the A/C system. This prevents any refrigerant from escaping into the atmosphere.
3. Once the purified refrigerant from the charging system has been transferred to an external compressed-gas cylinder, close the hand shut-off valves at the cylinder and charging system.
4. Do not expose charging system to moisture or use it in a wet environment.
5. Disconnect from power supply before performing service work on the charging system.
6. Never use an extension cable on account of the fire hazard. If the use of an extension cable is unavoidable, the minimum cross-section should be 2.5 mm 2 .
7. In case of fire, remove external cylinder.
8. Entrained oil from the air conditioning system drawn by the suction unit into the measurement vessel supplied is subsequently to be transferred to a sealed container as it contains a small quantity of refrigerant. It must not be released into the environment.
9. Following shutdown, service station is to be secured to stop it rolling away.

HANDLING PRESSURE VESSELS

1. Secure vessels to prevent them falling over!

Secure upright cylinders to stop them falling over and cylinders lying flat to stop them rolling away.

1. Do not throw vessels.

If dropped, the vessels could be so severely deformed that they rupture. The refrigerant evaporates immediately, liberating considerable force. Flying fragments of cylinders can cause severe injuries.

Valves may break off if cylinders are not properly transported. To protect the valves, cylinders are only to be transported with protective cap screwed on.

1. Never store in the vicinity of radiators.

High temperatures may occur next to radiators. High temperatures are also accompanied by high pressures and the maximum permissible vessel pressure may be exceeded.

Temperature Warning

To avoid possible risk, pressure vessel regulations specify that vessels are not to be heated to in excess of 50°C (122°F).

Heating Warning

Do not heat with a naked flame under any circumstances. Localized overheating can cause structural changes in the vessel material, which then reduce its ability to withstand pressure. There is also a danger of refrigerant decomposition due to localized overheating.

Empty Containers

Empty refrigerant vessels must always be sealed to prevent the ingress of moisture. Moisture causes steel vessels to corrode. This weakens the vessel walls. In addition, rust particles entering into refrigeration systems from vessels will cause malfunctioning.

HANDLING REFRIGERANT

Follow the instructions for the workplace. Refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment. They should be displayed in the workplace.

If refrigerant vessels are opened, the contents may escape in liquid or vapor form. This process is intensified the higher the pressure in the vessel.

The pressure level is governed by two factors

1. The type of refrigerant in the vessel. The lower the boiling point, the higher the pressure.
2. The temperature level. The higher the temperature, the higher the pressure.

Protective Eyewear

Put on protective goggles. They prevent refrigerant getting into the eyes, as this could cause severe injury from exposure to cold.

Protective Gloves and Clothing

Greases and oils dissolve readily in refrigerants. They would therefore destroy the protective layer of grease if allowed to come into contact with the skin. Degreased skin is however sensitive to the cold and germs.

Fluid Refrigerant and Skin Precaution

The refrigerant draws heat for evaporation from the surrounding area. Even if this is the skin. This may cause extremely low temperatures. Local frost bite may result (boiling point of R134a: -26.5°C (-15.7°F) at ambient pressure).

Do Not Breathe In Refrigerant Vapor

Note. If highly concentrated refrigerant vapor escapes, it mixes with the surrounding air and displaces the oxygen necessary for breathing.

Smoking Hazard

A burning cigarette can cause refrigerant to decompose. The resultant substances are toxic and must not be inhaled.

Welding and Soldering on Refrigeration Systems

Before performing welding or soldering work on vehicles near the air conditioning system components, extract the refrigerant and remove the residue by flushing with compressed air and nitrogen.

The products of refrigerant decomposition due to the effect of heat are not only toxic, but may also have a highly corrosive effect on pipes and system components. They mainly take the form of hydrogen fluoride.

Pungent Odor

A pungent odor indicates that the products of decomposition mentioned above have already formed. Avoid inhaling these substances under all circumstances, as otherwise the respiratory system, lungs and other organs could be damaged.

First Aid

1. Following contact with eyes or mucous membranes, immediately rinse with copious amounts of running water and consult an eye specialist.
2. Following contact with the skin, immediately remove affected clothing and rinse skin with copious amounts of water.
3. Following inhalation of highly concentrated refrigerant vapors, immediately take the affected person into the open air. Call a doctor. Administer oxygen in the event of breathing difficulties. If the affected person has difficulty breathing or cannot breathe, tip head back and perform mouth to mouth respiration.

REFRIGERANT R134A

Vehicle air conditioning systems make use of the vaporization and condensation process. In this case, one works with a substance which boils easily, designated as refrigerant.

The refrigerant employed is tetrafluoroethane R134a, which boils at -26.5°C (-15.7°F) at a vapor pressure of 1 bar.

Refrigerant R134a Environmental Information

1. R134a is a fluorocarbon and contains no chlorine.
2. R134a has a shorter atmospheric life span than refrigerant R12.
3. R134a does not damage the ozone layer. The ozone depletion potential is zero.
4. The greenhouse potential of R134a (Global Warming Potential (GWP)) is approximately 1300 (the GWP of carbon dioxide is 1).
5. The global warming effect of R134a is ten times less than that of refrigerant R12.

Vehicles manufactured after 1992 have air conditioning systems that use refrigerant R134a. This refrigerant does not contain chlorine and does not deplete the ozone layer.

Refrigerant R12 was used through 1992. Due to its chlorine atoms, this CFC has a high potential for depleting the ozone layer as well as a tendency to increase the greenhouse effect.

Conversions are offered for existing systems filled with the ozone-depleting substance R12.

Refer to Repair Information for A/C systems with refrigerant R12. This repair information is only available in hard copy.

For environmental protection reasons, refrigerants must not be released into the atmosphere. For laws and regulations, refer to LAWS AND REGULATIONS .

Refrigerant R134a Physical Data

Critical Point

The critical point (critical temperature and critical pressure) is that above which there is no longer a boundary between liquid and gas.

A substance above its critical point is always in the gaseous state.

At temperatures below the critical point, all types of refrigerant in pressure vessels exhibit both a liquid and a gas phase, for example, there is a layer of gas above the liquid.

As long as there is still gas present in the container next to the fluid, pressure is dependent on ambient temperature. Refer to REFRIGERANT R134A VAPOR PRESSURE TABLE .

Note. Different types of refrigerant are never to be mixed. Only the refrigerant designated for the corresponding A/C system may be used.

REFRIGERANT R134A CHARACTERISTICS

The vapor pressure curves of R134a and other refrigerants are sometimes very similar, therefore it is not possible to make a certain distinction solely by pressure.

With R134a, the A/C compressor is lubricated with special synthetic refrigerant oils, for example, PAG oils (polyalkylene glycol oils).

Trade Names and Designations

Refrigerant R134a is currently available under the following trade names

1. H-FKW 134a
2. SUVA 134a
3. KLEA 134a

Note. Different trade names may be used in other countries. Of the wide range of refrigerants available, this is the only one which may be used for vehicles. The designations Frigen and Freon are trade names. They also apply to refrigerants which may not be used in automotive vehicles.

Product Characteristics

Refrigerants used in motor vehicle air conditioning systems belong to the new generation of refrigerants based on chlorine-free, partially fluorinated hydrocarbons (H-FKW, R134a).

With regard to their physical properties, these are refrigerants which have been liquefied under pressure. They are subject to the regulations governing pressure vessels and use is only to be made of approved and appropriately marked containers.

Compliance with specific conditions is required to ensure safe and proper use.

Color

Like water, refrigerants are colorless in both vapor and liquid form. Gas is invisible. Only the boundary layer between gas and liquid is visible. (Liquid level in tube of charging cylinder or bubbles in sight glass). Refrigerant R134a fluid may appear colored (milky) in a sight glass. This cloudiness is caused by partially dissolved refrigerant oil and does not indicate a malfunction.

Vapor Pressure

In a partially filled, closed vessel, the quantity of refrigerant evaporating from the surface equals the quantity returning to the liquid state as vapor particles condense. This state of equilibrium occurs under the influence of pressure and is often called vapor pressure. Vapor pressure is dependent on temperature. Refer to REFRIGERANT R134A VAPOR PRESSURE TABLE .

Affect on Metal

In its pure state, refrigerant R134a is chemically stable and does not corrode iron or aluminum.

Refrigerant impurities such as chlorine compounds however cause corrosion of certain metals and plastics. This can lead to blockage, leaks or deposits on the A/C compressor piston.

Critical Temperature/Pressure

The refrigerant R134a remains chemically stable up to a gas pressure of 39.5 bar (corresponding to a temperature of 101°C (213°F). Above this temperature, the refrigerant decomposes (refer to Combustibility ).

Water Content

Only very small amounts of water are soluble in liquid refrigerant. On the other hand, refrigerant vapor and water vapor mix in any ratio.

Only a small drop of water may get into the refrigerant circuit. The dryer, dryer bag or dryer cartridge contained in the reservoir can absorb approximately 7 grams (0.25 oz.) of water. They are then saturated and cannot absorb any more water. If water is still present in the refrigerant circuit, it flows up to the expansion valve nozzle or restrictor and becomes ice.

The air conditioning system stops cooling.

Water destroys the air conditioner as it combines with other impurities at high pressures and temperatures to form acids.

Combustibility

Refrigerant is non-flammable. It actually has a fire resistant or fire extinguishing effect. Refrigerant decomposes when exposed to flames or red-hot surfaces. UV light (occurring for example during electric welding) also causes refrigerant decomposition. The resultant decomposition products are toxic and are not to be inhaled. However, irritation of the mucous membranes provides an adequate and timely warning.

Charge Factor

A vessel must have space for vapor as well as liquid. As the temperature rises, the liquid expands. The vapor-filled space becomes smaller. At a certain point, there will only be liquid in the vessel. Beyond this, even a slight increase in temperature causes great pressure to build up in the vessel as the liquid attempts to continue expanding despite the absence of the necessary space. The forces that result are strong enough to rupture the vessel. To prevent a vessel from being overfilled, the regulations regarding compresses gasses specify how many kilograms of refrigerant that may be added to a vessel per liter of interior volume. Multiplying this filling factor with the interior volume gives the permitted filling capacity. The figure for refrigerant used in vehicles is 1.15 kg/liter.

Evidence of Leaks

External damage, for example, can cause a leak in the refrigerant circuit. The small quantity of refrigerant escaping from minor leaks can be detected for example using an electronic leak detector or by introducing a leak detection additive into the refrigerant circuit. Electronic leak detectors are capable of registering leaks with refrigerant losses of less than 5 g per year. Use leak detectors designed for the type of refrigerant. For example, a leak detector for R12 refrigerant will not work with R134a because R134a refrigerant has no chlorine atoms so the leak detector will not respond to it.

REFRIGERANT R134A VAPOR PRESSURE TABLE

The vapor pressure table for every refrigerant is published in literature for refrigeration system engineers. This table makes it possible to determine the vapor pressure acting on the column of liquid in a vessel if the temperature of the vessel is known.

Because each refrigerant has its own characteristic vapor pressure table, refrigerant can be identified by measuring the pressure and temperature.

Note. At absolute pressure, 0 bar corresponds to absolute vacuum. Normal ambient pressure (positive pressure) corresponds to 1 bar absolute pressure. 0 pressure corresponds to an absolute pressure of one bar on most pressure gauges (indicated by -1 bar below 0).

REFRIGERANT OIL

Refrigerant oil mixes with the refrigerant (about 20 - 40%, depending on compressor type and amount of refrigerant) and circulates constantly in the system, lubricating the moving parts.

Special synthetic refrigerant oils, for example polyalkylene glycol (PAG) oil, are used in conjunction with R134a air conditioning systems. This is necessary as mineral oil, for example, does not mix with R134a. In addition, the materials of the R134a air conditioning system could be corroded as a result of mixture flowing through the refrigerant circuit under pressure at high temperatures or breakdown of the lubricating film in the compressor. Using non-approved oils can cause the HVAC system to malfunction. Only use approved oils.

Type of oil for R134a in motor vehicles: PAG

Note. Do not store open containers of refrigerant oil because it attracts moisture. Always keep oil containers sealed. Do not use old refrigerant oil over again. Dispose of old oil. Refer to Volkswagen-Service Net, Handbook, Handbook Service Germany; 15. Environment Protection; further with Environmental Protection; 7 emission protection; refrigerant oil. Ester-based oils are only intended for use in large systems, not in passenger vehicle systems.

REFRIGERANT OIL CHARACTERISTICS

The most important properties are a high degree of solubility with refrigerant, good lubricity, absence of acid and minimal water content. Only certain oils are permitted. For a list of approved refrigerant oils and capacities, refer to MAINTENANCE, DIAGNOSIS .

PAG oils, which are appropriate for refrigerant R134a, are highly hygroscopic and do not mix with other oils. Opened containers should therefore be closed again immediately to prevent ingress of moisture. Moisture and acids promote aging of refrigerant oil, causing it to become dark and viscous as well as corrosive towards metals.

Note. Only use oils approved for the A/C compressor in refrigerant circuits with refrigerant R134a. For capacities, refer to MAINTENANCE, DIAGNOSIS . Dispose of old oil. Refer to Volkswagen-Service Net, Handbook, Handbook Service Germany; 15. Environment Protection; further with Environmental Protection; 7 emission protection; refrigerant oil.

SERVICING A/C SYSTEM

The purpose of this Repair Information is to provide foremen and mechanics with the basic knowledge needed to ensure expert working.

Note. Expert knowledge is achieved by one who has taken part successfully in instructional training for example, AB160 or ST160, including trained experts. This Repair Information also serves as instructional material.

It should also be available for presentation to the responsible supervisory agency on request.

Additional Information Sources

1. Technical Service Handbook outlining action to be taken to rectify current problems.
2. Repair Information for type-specific servicing work, refer to «[For engine(s) BPY, CCTA, BUB, CBFA] Air Conditioning»(ref-475571-S42791858232012052300000) .
3. Refer to appropriate System Wiring Diagram information.
4. Sections of Self Study Program number 208 are no longer up-to-date. An example of this is the statement "The fluid reservoir is replaced each time the refrigerant circuit is opened". The following prerequisites apply. Refer to «NOT REPLACING RESERVOIR/FLUID RESERVOIR OR DRYER BAG/CARTRIDGE, CONDITIONS»(ref-475566-S16804876332012052300000) .
5. Video programs for in-dealership training.
6. Special Tools and Workshop Equipment Information.
7. Service Organization Volume 1 Additional Equipment.
8. Repair information Air Conditioning with Refrigerant R12. Only hardcopies of this information are available for vehicles through MY 1993.
9. The procedure for flushing the refrigerant circuit is selected in Volkswagen Service Net; Volkswagen TV; API Online; or Volkswagen TV Net; API/PKW under the book title Body and then the program from June 8, 2005 Refrigerant Circuit, Flushing, Golf Plus.

ULTRASOUND A/C CLEANER -VAS 6189A

The Ultrasound A/C Cleaner -VAS 6189A- is placed in the front passenger footwell and sprays Aero-Clean. Aero-Clean neutralizes microbes and bacteria inside the heater and A/C unit.

The unit comes with Operating Instructions.

For the current units, refer to relevant information in Service Net; Workshop Equipment; ; V.A.G Workshop Equipment ; A/C and Heater; Service Units.

CHARGING SYSTEMS NOT REQUIRING A PERMIT

Charging systems not requiring a permit are ones used for transferring compressed gases to mobile compressed-gas vessels for internal use only.

Note

Some A/C service units are charging systems not requiring a permit. When working with such equipment, the refrigerant is not transferred to mobile compressed-gas vessels, but rather into a permanently installed charging cylinder with visible level gauge and float switch.

Recommendation

It is advisable to use a portable cylinder with visible level gauge and pressure relief valve for surplus refrigerant for internal use.

Attention must be paid to TRG 402 (technical regulations for compressed gases) when transferring compressed gases to other compressed-gas vessels.

EXTRACTION SYSTEM GROUP CLASSIFICATIONS

Group 3

Mobile extraction and charging systems for filling compressed-gas vessels permanently connected to the system.

The refrigerant or refrigerant/oil mixture is transferred to compressed gas vessels which are permanently connected to the mobile systems. In accordance with 3 Paragraph 5 No. 3 of pressure vessel regulations, compressed-gas vessels are classified as pressure vessels in this case.

The charging systems require

1. No permit
2. No expert testing as the gas is transferred to compressed-gas vessels which are classed as being pressure vessels. (Systems used for transfer from these pressure vessels to compressed-gas vessels for supplying to third parties do require a permit and are subject to mandatory testing).

Note. The A/C service and recycling units used in motor vehicle workshops are extraction and charging systems not requiring a permit (Group "3") but which are only to be operated by qualified personnel. Instructions for unit operation and maintenance can be found in the relevant manufacturer's documentation.

LAWS AND REGULATIONS

Note. The laws and regulations listed below are applicable in Germany. Different or additional laws and regulations may apply in other countries. Addresses in other countries can be obtained from the relevant authorities.

The effects of climate change can be seen worldwide. Protecting the climate is one of the most important responsibilities. However, this responsibility presents enormous challenges to all involved.

The Kyoto Protocol outlines worldwide goals regarding climate protection, among other things. In addition to target reductions of carbon dioxide, this protocol also outlines target reductions for fluorinated greenhouse gases such as refrigerant R134a due to their high potential of contributing to the greenhouse effect.

Numerous laws have been created for the automotive industry, for example at the European level. For example, chemical-climate protection regulations were put into effect on August 1, 2008 in Germany in order to define the European legislation in more detail.

1. Provision (EU) no. 1005/2009
2. Provision (EU) no. 842/2006
3. Provision (EU) no. 706/2007
4. Provision (EU) no. 307/2008
5. Guideline 2006/40/EU
6. Chemical-climate protection provision, recycling management and disposal regulations (for Germany)

Maintenance and repair work on the A/C system refrigerant circuit

All individuals performing maintenance and repair work on vehicle A/C systems must have completed a training program and be competent in the work required. Other regulations may apply in addition to those of the European Union.

The following general points apply

Operation, repair, decommissioning, take-back obligation

1. When operating, repairing and decommissioning items that contain refrigerant, allowing the refrigerant to vent into the air is prohibited.
2. Keep records about the quantities used during operation and maintenance (Refrigerant Log, refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment; Emission Protection) so they can be presented to the authorities upon request. Other provisions may apply in countries that are not members of the EU.
3. Distributors of the substances and preparations discussed above are obligated to accept these items back after use or to ensure they are accepted by a third party of their choosing.
4. Maintenance and decommissioning of items containing refrigerant that are named in the legislation Substances and preparations named in this legislation may only be accepted by those with the necessary expertise and technical equipment.

Criminal offenses and infringements of the law

1. Willfully or negligently venting refrigerant into the air when operating, repairing or decommissioning items that contain refrigerant constitutes a violation of the laws and legislation described above.

Technical Regulations For Compressed Gases (TRG) 400, 401, 402

Only excerpts concerning vehicle manufacturers and workshops are listed below.

TRG 400 (General Regulations For Charging Systems)

2. Definition of terms and explanations

2. 1 Charging systems

2.1.1 Charging systems are systems for filling mobile compressed-gas vessels. The charging system includes the premises and facilities concerned.

2. 4 Charging systems requiring a permit

Charging systems requiring a permit are ones used to transfer compressed gases to mobile compressed-gas vessels for supplying to third parties.

5 Charging systems not requiring a permit are ones used for transferring compressed gases to mobile compressed-gas vessels for internal use only.

TRG 401 (Installation Of Charging Systems)

Does not apply to vehicle manufacturers or workshops.

TRG 402 (Operation Of Charging Systems)

2. Employees and employee instruction

2. 1 Charging systems are only to be operated and maintained by personnel

1. Who are 18 years of age and older
2. Who possess the necessary technical knowledge
3. Who can be relied upon to work diligently.

2. 2 Supervised work may also be performed by personnel that do not meet the requirements stipulated in item 2. 1, points 1 and 2.

2. 3 Employees are to be given instruction on the following topics before beginning work and at regular, appropriate intervals, however at least once a year

1. Hazards specifically associated with handling compressed gases
2. Safety regulations, particularly the applicable TRG
3. Procedures in the event of malfunction, damage and accidents
4. The use of fire-extinguishing and protective equipment
5. Operation and maintenance of the charging system according to the operating instructions.

Charging (a separate TRG applies to vessels from other countries and their charging)

A compressed-gas vessel is only to be filled with the compressed gas declared on it and the quantity must comply with the stipulated pressure, weight or volume data (refer to g15, Para. 2, pressure vessel regulations).

2. In the case of vessels approved for use with several types of compressed gas, the compressed gas with which it is to be filled and - if the compressed gas has a tk greater than or equal to -10°C (14°F) (tk = critical temperature) - the maximum permissible charging weight in line with TRG 104 No. 3. 3 must be marked on the vessel prior to connection for filling.

3. Compressed-gas vessels marked with the maximum permissible charge pressure in bar at 15°C (59°F) must be filled manometrically. If, at the time of filling, the temperature is not 15°C (59°F), the pressure corresponding to the prevailing temperature must be established; it must be ensured that the permissible charge pressure at 15°C (59°F) is not exceeded in the compressed- gas vessel. The charged vessels are to be checked by way of random pressure measurements to determine possible overfilling.

4. Compressed-gas vessels on which the maximum permissible capacity is indicated by the net weight (filling weight, permissible weight of fill) in kilograms must be filled gravimetrically. The vessels are to be weighed during filling and subsequently subjected to a weight check on special scales to establish possible overfilling. Scales used for this purpose must be calibrated.

5. Under certain conditions, gases with a tk greater than or equal to 70°C (158°F) may be transferred volumetrically from compressed-gas vessels with a maximum volume of 150 l to compressed-gas vessels with a volume of maximum 1000 ccm. The stipulations of the TRG apply to the transfer of liquefied gas to cylinders used by workmen.

6. Vessels in vehicles for

(1) Gases with tk greater than or equal to +70°C (158°F) (refer to TRG 101 Annex 3)

(2) Industrial gas mixtures with tk greater than or equal to +70°C (158°F) (refer to TRG 102 Annex 1 Groups 3) or

Liquefied extremely low-temperature compressed gases (refer to TRG 103) may, contrary to item 4, be filled volumetrically if the charging system and/or the vessels is/are equipped with devices for measuring or limiting the volume of the charge and - with the exception of motor vehicle vessels as per item 3 - for measuring the temperature of the charge. When filling volumetrically, it must be ensured that the permissible charge weight indicated on the vessel is not exceeded. To determine possible overfilling, the filled containers are to be checked gravimetrically on a calibrated scale or - provided that the pressurized gases are not highly toxic - volumetrically. Volumetric checking requires the use of appropriate equipment with completely separate charging and checking devices.

7. Charging and check measurements are to be performed by different people. Check measurements must be performed immediately upon completion of the filling process.

8. Overfilled vessels must be drained immediately and in a safe manner until the permissible fill is attained. The compressed-gas fill is then to be determined again.

9. Items 4 to 7 do not apply to vessels for liquefied, extremely low-temperature compressed gases which are neither flammable nor toxic; this does not affect the provisions of road traffic legislation.

10. When filling compressed gas vessels with liquefied gases at charging temperatures less than or equal to -20°C (-4°F), the compressed gas vessel (if the vessel material has not been tested for temperatures less than or equal to -20°C (-4°F) is not to be released from the charging system for transportation until the vessel wall temperature is greater than or equal to +20°C (68°F).

Recycling and Disposal Regulations

Specifications and rules for handling and disposing of refrigerants and refrigerant oils can be found in the chemical-climate protection provision and recycling and disposal regulations. These are valid in Germany. Different specifications and rules may apply in other countries.

Refrigerant, Keeping Records

The environmental statistics law requires records to be kept on the use of refrigerants.

Consequently, motor vehicle workshops may well have to provide the relevant local authorities with information on their use of refrigerant. It is therefore recommended to keep records of the quantities used during operation and maintenance (refrigerant log) and present them to the relevant authorities upon request.

Note. Other provisions may apply in countries that are not members of the EU.

RECYCLING AND DISPOSAL REGULATIONS

Note. The laws and regulations listed below are applicable in Germany. Different or additional laws and regulations may apply in other countries. Addresses in other countries can be obtained from the relevant authorities.

Specifications and rules for handling and disposing of refrigerants and refrigerant oils can be found in the chemical-climate protection provision and recycling and disposal regulations. These are valid in Germany. Different specifications and rules may apply in other countries.

Refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment; Waste Disposal.

Refrigerant Disposal

Refrigerants intended for disposal are to be transferred to marked recycling containers, observing the permissible filling quantity. Refer to the chemical-climate protection provision and the recycling and disposal regulations in Germany. Different specifications and rules may apply in other countries.

Refrigerant Oil Disposal

Used refrigerant oils from systems employing halogenated hydrocarbons are to be disposed of as waste subject to special supervision. They are not to be mixed with other oils or substances. Proper storage and disposal must be ensured in line with local regulations. Refer to the chemical-climate protection provision and the recycling and disposal regulations in Germany. Different specifications and rules may apply in other countries.

Addresses in other countries can be obtained from the relevant authorities.

REFRIGERANT CIRCUIT, CONVERTING R12 TO R134A AND SERVICING

Note. The laws and regulations listed below are applicable in Germany. Different or additional laws and regulations may apply in other countries. Addresses in other countries can be obtained from the relevant authorities. For environmental reasons and on account of the corresponding legislation, refrigerant R12 can no longer be manufactured or supplied. Refrigerant R134a has been developed as a replacement for R12. Air conditioning systems developed and designed for refrigerant R12 cannot however simply be charged with refrigerant R134a. To ensure trouble-free operation of the air conditioning system even after conversion, various components of the refrigerant circuit must be replaced. A precise description of the conversion procedure and information on the servicing of converted refrigerant circuits can be found in Repair Information: Air conditioner with refrigerant R12 Parts 2 and 3. This repair information is only available in hard copy.

REFRIGERANT, KEEPING RECORDS

Note. The laws and regulations listed below are applicable in Germany. Different or additional laws and regulations may apply in other countries. Addresses in other countries can be obtained from the relevant authorities.

Keep records about the quantities used during operation and maintenance (Refrigerant Log, refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment; Emission Protection) so they can be presented to the authorities upon request. Other provisions may apply in countries that are not members of the EU.

PHYSICAL PRINCIPLES

The four known states of water also apply to air conditioning system refrigerants.

Scheme 8

1. Gaseous (invisible)
2. Vapor
3. Fluid
4. Solid

When water is heated in a vessel (heat absorption), water vapor can be seen to rise. If the vapor is further heated through heat absorption, the visible vapor turns into invisible gas. The process is reversible. The warmth is extracted from gaseous water, vapor forms first, then water and then ice.

Scheme 9

A - Heat absorption

B - Heat emission

Heat Transfer

Every substance consists of a mass of moving molecules. The fast moving molecules of a warmer substance give off some of their energy to the cooler and thus slower molecules. As a result, the molecular motion of the warmer substance slows down and that of the colder substance is accelerated. This process continues until the molecules of both substances are moving at the same speed. They are then at the same temperature and no further heat exchange takes place.

PRESSURE AND BOILING POINT

The boiling point given in tables for a liquid is always referenced to an atmospheric pressure of 1 bar. If the pressure acting on a fluid changes, its boiling point also changes.

For example, water boils at a lower temperature the lower the pressure.

The vapor pressure curves for water and refrigerant R134a show that, at constant pressure, reducing the temperature changes vapor to liquid (in the condenser) or that reducing the pressure causes the refrigerant to change from liquid to vapor (evaporator).

Vapor pressure curve of water

Scheme 10

A - Fluid

B - Gaseous

C - Vapor pressure curve of water

1 - Pressure acting on liquid in bar (absolute)

2 - Temperature in °C

Vapor pressure curve of refrigerant R134a

Scheme 11

A - Fluid

B - Gaseous

D - Vapor pressure curve of refrigerant R134a

1 - Pressure acting on liquid in bar (absolute)

2 - Temperature in °C

COMFORT

Being comfortable while driving leads to better concentration and safe driving. Air conditioning makes drivers and passengers more comfortable when temperatures or humidity are high. While opening the windows or sunroof or increasing the air flow can make vehicle occupants more comfortable, it also exposes them to more noise, draughts, exhaust, pollen and dust.

A well-designed heating and air conditioning system can increase comfort by controlling the temperature, humidity and air flow inside the vehicle. This is done both when the vehicle is moving and when it is stationary.

Air conditioning also offers these advantages

1. It cleans the air that enters the vehicle interior. The damp fins on the evaporator collect dust and pollen, which is then removed by condensation.
2. Temperatures in a mid-size vehicle (for example: after a short drive, outside temperature 30°C in the shade and the vehicle exposed to sunlight).

REFRIGERANT CIRCUIT, GENERAL PRECAUTIONS

1. Follow the instructions for the workplace. Refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment. They should be displayed in the workplace.
2. Ensure absolute cleanliness when working.
3. Wear work clothing, safety goggles and gloves when working with refrigerant and nitrogen.
4. Turn on the exhaust gas ventilation system
5. Use service station to discharge refrigerant circuit, only then open screw connections and replace malfunctioning components.
6. Use caps to seal off opened assemblies and hoses to prevent ingress of moisture and dirt.
7. Make exclusive use of tools and materials intended for refrigerant R134a.
8. Be sure to close the container to prevent the refrigerant from absorbing moisture from the air.

Flushing refrigerant circuit with compressed air and nitrogen, refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN .

Flush the refrigerant circuit with R134a refrigerant. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A .

On vehicles with A/C compressor without magnetic clutch

Note. The engine should only be started after assembling the refrigerant circuit. If possible start engine only with a filled refrigerant circuit. The A/C compressor is always driven by the ribbed belt pulley/torsion elastic clutch. It does not have a magnetic clutch. If an A/C compressor locks-up the overload protection for the A/C compressor shaft is triggered. If no bumps are visible on the ribbed belt pulley/overload protection, the A/C compressor may be blocked. Another indicator is abraded rubber material in the area of the ribbed belt pulley/overload protection The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm 3 of refrigerant oil remains in the A/C compressor. The engine may only be started when the refrigerant circuit is installed correctly. For example; if the refrigerant pipes are not connected to A/C compressor, when the engine is running the A/C compressor may heat up (via internal heat generation) so much that the A/C compressor will be damaged. A/C Compressor Regulator Valve -N280- is not activated when the refrigerant circuit is empty and the A/C compressor idles with the engine. If it is necessary to start the engine with a discharged refrigerant circuit: Refrigerant circuit must be fully assembled. At least 1/4 of the prescribed refrigerant oil must be in the A/C compressor. Do not rev engine higher than 2000 RPM. The engine should run less than 10 minutes.

O-RING SEALS

1. Only O-rings that are resistant to refrigerant R134a and refrigerant oil must be installed. Color coding of O-rings is no longer employed. Colored and black O-rings are used.
2. Ensure inner diameter on seals used is correct.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

1. The O-rings may be used one time only.
2. Before installing O-rings, coat lightly with refrigerant oil (PAG oil).

Note. When flushing components with compressed air and nitrogen, always extract the gas mixture escaping from the components with suitable extraction units (workshop extraction system). After engine all service work, screw sealing caps (with seals) onto all connections with valve and service connections.

Before starting up A/C system. Observe vehicle specific filling capacities. Refer to MAINTENANCE, DIAGNOSIS .

Do not fill refrigerant, extract refrigerant present and refill the system.

REFRIGERANT CIRCUIT PIPES AND HOSES

The mixture of refrigerant oil and refrigerant R134a corrodes certain metals (for example copper) and alloys and dissolves some hose materials. Therefore use original replacement parts only.

Pipes and hoses are joined by threaded connections or special plug connectors.

Note. Observe specified torque for threaded connections, use appropriate release tools for plug connectors.

REFRIGERANT CIRCUIT PRESSURES AND TEMPERATURES

The pressures and temperatures in the refrigerant circuit depend on the current operating conditions (such as engine RPM, coolant fan level 1, 2 or 3, engine temperature, A/C compressor on or off) as well as on the effects of outside influences (such as outside temperature, humidity, desired cooling output).

In vehicles with A/C compressor regulator valve -N280-, the pressure is modified on the low pressure side by the valve.

For this reason, values indicated in the following table are valid only as reference points. They are attained at an engine speed of 1500 to 2000 RPM and an ambient temperature of 20°C (68°F) after about 20 minutes.

The connections provided for measuring pressure for the manometer battery are located in the vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

At 20°C (68°F) with the engine not running, the pressure in the refrigerant circuit is 4.7 bar. Refer to REFRIGERANT R134A VAPOR PRESSURE TABLE .

REFRIGERANT CIRCUIT, CONVERTING R12 TO R134A

CFC refrigerants are no longer used in the automotive industry.

Converting refrigerant circuits from R12 refrigerant to R134a refrigerant and servicing converted circuits, refer to Repair Information Air conditioner with refrigerant R12 Parts 2 and 3. This repair information is only available in hard copy.

A/C COMPRESSOR WITH MAGNETIC CLUTCH

The engine drives the A/C compressor via a ribbed belt.

Scheme 12

An electromagnetic clutch installed on the A/C compressor creates a frictional connection between the ribbed belt pulley and A/C compressor crankshaft when the air conditioning system is switched on.

If the A/C compressor sticks, a fuse installed in the compressor ribbed belt pulley releases the electromagnetic clutch and protects the ribbed belt pulley from overload.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note. The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature. The type plate lists the type of refrigerant required for the A/C compressor. A regulator valve regulates pressure within the specified range (control characteristics) on the low pressure side. So that the A/C compressor does not get damaged when the refrigerant circuit is empty, the A/C clutch is turned off and the A/C compressor regulator valve -N280- is no longer activated (A/C compressor runs at idle with engine).

A/C COMPRESSOR WITHOUT MAGNETIC CLUTCH

The engine drives the A/C compressor via a ribbed belt.

Scheme 13

Overload protection (shear) installed in the A/C compressor ribbed belt pulley releases when the compressor stops and protects the ribbed belt pulley from being overloaded.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note. The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature. The type plate lists the type of refrigerant required for the A/C compressor. A regulator valve regulates pressure within the specified range (control characteristics) on the low pressure side. On this A/C compressor, the control valve is activated from outside. The engine should only be started if the refrigerant circuit is completely assembled. Refer to REFRIGERANT CIRCUIT, GENERAL PRECAUTIONS . The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm 3 of refrigerant oil remains in the A/C compressor.

A/C COMPRESSOR WITHOUT MAGNETIC CLUTCH WITH TORSION-ELASTIC CLUTCH

The A/C compressor is driven directly by the power steering vane pump.

Scheme 14

On the A/C compressor driveshaft, there is an overload protection that shears off when the compressor is blocked so that the power steering vane pump remains functional.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note. The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature. The type plate lists the type of refrigerant required for the A/C compressor. A regulator valve regulates pressure within the specified range (control characteristics) on the low pressure side. On this A/C compressor, the control valve is activated from outside. The engine should only be started if the refrigerant circuit is completely assembled. Refer to REFRIGERANT CIRCUIT, GENERAL PRECAUTIONS . The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm 3 of refrigerant oil remains in the A/C compressor.

CONDENSER

The condenser conducts heat from compressed refrigerant gas to the ambient air.

Scheme 15

This condenses the refrigerant gas to fluid.

E-COMPRESSOR FOR HYBRID VEHICLES

E-A/C Compressor

Scheme 16

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note. The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature. The type plate lists the type of refrigerant required for the A/C compressor. The RPM controls the delivery. The engine should only be started if the refrigerant circuit is completely assembled. Refer to REFRIGERANT CIRCUIT, GENERAL PRECAUTIONS . The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm 3 of refrigerant oil remains in the A/C compressor. The A/C compressor has a relief valve.

EVAPORATOR

The fluid refrigerant evaporates in the evaporator pipe coils. The heat required for this is extracted from the air flowing on the evaporator ribbing. The air cools off. Refrigerant evaporates and is extracted with the absorbed heat by the A/C compressor.

Scheme 17

A defined amount of refrigerant is supplied to the evaporator by a restrictor or expansion valve. In systems with expansion valve, the throughput is regulated so that only gaseous refrigerant escapes the evaporator outlet.

EVACUATING AND CHARGING VALVE WITH SCHRADER VALVE

Special tools and workshop equipment required

1. Torque Wrench -V.A.G 1783- (2 to 10 Nm) with 1/4" socket -VAS 6234

1. Only valves and connections that are resistant to refrigerant R134a and refrigerant oil must be installed.
2. Different connections (outer diameter) for high pressure and low pressure side.
3. Always screw on sealing caps.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation

Scheme 18

Note. Torque wrench -V.A.G 1783- with 1/4" socket -VAS 6234- Use a suitable socket -T10364- to loosen the Schrader valve insert. Refer to Socket T10364 for the high pressure/low pressure side service connection valves in the refrigerant circuit .

A - Service connection (soldered in)

B - Schrader valve insert (2.4 +/- 0.2 Nm)

C - O-ring (belongs to the valve)

D - Sealing cap with seal

EVACUATING AND CHARGING VALVE, HIGH PRESSURE SIDE

Special tools and workshop equipment required

1. Torque wrench -V.A.G 1783- (2 to 10 Nm) with 1/4" socket -VAS 6234

1. Only valves and connections that are resistant to refrigerant R134a and refrigerant oil must be installed.
2. Different connections (outer diameter) for high pressure and low pressure side.
3. Always screw on sealing caps.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Scheme 19

Note. Torque wrench -V.A.G 1783- with 1/4" socket -VAS 6234- Use a suitable socket -T10364- to loosen the valve insert.

1. Socket with external and internal threads
2. O-ring: 10.8 mm; 1.8 mm identification: black or with colors
3. Valve with M12 x 1.5 mm external threads and groove for O-ring (7 +/- 1 Nm)
4. O-ring for the cap: 10.8 mm; 1.8 mm identification: black or with colors
5. Cap

EVACUATING AND CHARGING VALVE, LOW PRESSURE SIDE

Special tools and workshop equipment required

1. Torque wrench -V.A.G 1783- (2 to 10 Nm) with 1/4" socket -VAS 6234

1. Only valves and connections that are resistant to refrigerant R134a and refrigerant oil must be installed.
2. Different connections (outer diameter) for high pressure and low pressure side.
3. Always screw on sealing caps.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Scheme 20

Note. Torque wrench -V.A.G 1783- with 1/4" socket -VAS 6234- Use a suitable socket -T10364- to loosen the valve insert.

1. Connection with external thread and groove for O-ring
2. O-ring: 7.6 mm; 1.8 mm identification: black or with colors
3. Valve with M10 x 1.25 mm external threads and groove for O-ring (7 +/- 1 Nm)
4. O-ring for the cap: 7.6 mm; 1.8 mm identification: black or with colors
5. Cap

EXPANSION VALVE

The expansion valve atomizes the streaming refrigerant and controls the flow quantity so that the vapor is gaseous only at the evaporator outlet, depending on the heat transmission.

Scheme 21

HIGH AND LOW PRESSURE SIDES

High pressure side are the condenser, receiver and restrictor or expansion valve to separate the high and low pressure liquid ends.

High pressure results from the restrictor or expansion valve forming a constriction and causing the refrigerant to accumulate, thus leading to an increase in pressure and temperature.

Excess pressure results if too much refrigerant or refrigerant oil is used, the condenser is contaminated, the radiator fan is malfunctioning, the system is blocked or if there is moisture in the refrigerant circuit (the restrictor or expansion valve freezes).

Low pressure side are the evaporator, reservoir, evaporator temperature sensor and compressor to separate high and low pressure gas ends.

A drop in system pressure can occur due to loss of refrigerant, restrictor or expansion valve (restriction not given), A/C compressor malfunction or iced evaporator.

These O-rings seal off the connection points between individual components of the refrigerant circuit.

Scheme 22

Only O-rings that are resistant to refrigerant R134a and refrigerant oil must be installed. Make sure they are original replacement parts.

O-ring

1. Always use only once.
2. Make sure diameters -a- and -b- are correct.
3. Moisten with refrigerant oil before installing.

Note. The color coding of refrigerant circuit o-rings with R134a has been discontinued. Colored and black O-rings are used.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

PRESSURE RELIEF VALVE

The pressure relief valve is installed on the A/C compressor or reservoir.

Scheme 23

At a pressure of approximately 38 bar positive pressure, valve opens and closes again once pressure has dissipated (approximately 30 bar).

Refrigerant does not escape completely.

Depending on the version, a transparent plastic disc may be installed which breaks off as soon as the valve is activated.

RESERVOIR

The reservoir collects the vaporized and gaseous mixture coming from the evaporator to ensure the compressor only receives gaseous refrigerant. Gaseous refrigerant is formed from the vapor.

Scheme 24

The refrigerant oil flowing in the circuit is not retained in the reservoir as it has an oil drilling.

Moisture which has entered the refrigerant circuit during repairs will be collected by a filter (desiccant bag) in the reservoir.

Gaseous refrigerant is extracted with oil by the A/C compressor.

Note. Replace the reservoir if refrigerant circuit has been open for a long time (beyond the normal repair time) and moisture has penetrated inside, or if required due to a specific complaint. Refer to COMPONENT REPLACEMENT . Remove sealing plugs -A- and -B- only immediately prior to installing. A desiccant bag in an unsealed reservoir is saturated with moisture after a short period of time and unusable. When installing, note arrow for direction of flow if necessary.

RESTRICTOR

The restrictor creates a constriction. This restriction reduces the flow and creates high and low pressure sides in the refrigerant circuit. Before the restrictor the refrigerant which is under a higher pressure is warm. After the restrictor the refrigerant which is under a low pressure is cold. Before the restriction there is a strainer for contaminants and after the restriction there is a strainer, to atomize the refrigerant before it reaches the evaporator.

Scheme 25

Note. Arrow -A- on restrictor points to evaporator. Replace after each opening of the circuit. Note different versions.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Scheme 26

1. Evaporator
2. Expansion Valve
3. Valve for extracting, filling and measuring
4. Reservoir with dryer bag/dryer cartridge
5. Condenser
6. A/C Compressor

Note. Arrows point in direction of refrigerant flow.

REFRIGERANT CIRCUIT WITH RESTRICTOR AND RESERVOIR

Arrows point in direction of refrigerant flow.

A- Low pressure side of refrigerant circuit.

B- High pressure side of refrigerant circuit

Scheme 27

Pressures on A-side are maintained at approximately 2 bar by regulating A/C compressor also at various engine speeds. However, this applies only within the performance range of the A/C compressor; if the performance limits of the A/C compressor are exceeded. Refer to PRESSURES, CHECKING .

Note. In vehicles with A/C compressor regulator valve -N280-, the pressure is modified on the low pressure side by the valve.

REFRIGERANT CIRCUIT WITH EXPANSION VALVE

A- Low pressure side of refrigerant circuit.

B- High pressure side of refrigerant circuit

Scheme 28

Note. A/C compressors which do not regulate their performance are switched off by the respective control module via the A/C compressor regulator valve -N280- at an evaporator temperature below 0°C (32°F). In vehicles with A/C compressor regulator valve -N280-, the pressure is modified on the low pressure side by the valve.

A/C COMPRESSOR REGULATOR VALVE -N280

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

The regulator valve is installed in the compressor. It is activated by the A/C Display Control Head -E87- or Climatronic Control Module -J255-. Pressure on the low pressure side is influenced via the regulator valve and thus regulates the temperature in the evaporator.

Scheme 29

Note. The A/C compressor regulator valve is a component of the A/C compressor and cannot be replaced separately.

A/C PRESSURE SWITCH -F129

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

This pressure switch has 3 functions

Scheme 30

1. Switches the coolant fan to the next higher level when the pressure in the refrigerant circuit increases (approximately 16 bar).

2. Switches off A/C system if pressure is excessive (approximately 32 bar), for example, because of insufficient engine cooling.

3. Switches off A/C system if pressure is insufficient (approximately 2 bar), for example, loss of refrigerant.

Note. A/C Pressure Switch -F129- replaces the A/C Refrigerant High Pressure Switch -F23-, A/C Refrigerant Low Pressure Switch -F73- and the A/C Refrigerant High Pressure Switch -F118-.

A/C PRESSURE/TEMPERATURE SENSOR -G395

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

This A/C Pressure/temperature Sensor -G395- is installed instead of the High Pressure Sensor -G65- or A/C Pressure Switch -F129-.

Scheme 31

The pressure signal is always being checked, where the temperature signal is only checked at temperatures above 32°F (0°C).

The Climatronic control module -J255- operates with this information and controls the coolant fans and activation of the A/C compressor regulator valve -N280-.

A/C REFRIGERANT HIGH PRESSURE SWITCH -F23

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

Function

Scheme 32

Switches the coolant fan to the next higher level when the pressure in the refrigerant circuit increases (approximately 16 bar).

A/C REFRIGERANT HIGH PRESSURE SWITCH -F118

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

Function

Switches off A/C compressor when there is excessive pressure in the refrigerant circuit (approximately 32 bar).

A/C REFRIGERANT LOW PRESSURE SWITCH -F73

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

Function

Scheme 33

Switches off A/C compressor when there is excessive pressure in the refrigerant circuit (approximately 2 bar).

HIGH PRESSURE SENSOR -G65

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

This high pressure sensor -G65- is installed in place of an A/C pressure switch -F129-.

Scheme 34

When a voltage is applied, the high pressure sensor generates a square wave signal or a data telegram. This signal changes along with pressure in the system.

The downstream control modules (coolant fan control module, ECM), A/C control head -E87- or Climatronic control module -J255-, etc.) use this signal to calculate pressure in the refrigerant circuit and to activate the coolant fans and motor and A/C clutch -N25- or to change the A/C compressor regulator valve -N280- activation.

REFRIGERANT CIRCUIT CONNECTIONS WITH VALVE FOR SWITCHES

Note. For switching pressures, removing and installing switches and switch arrangement and version, see vehicle-specific refrigerant circuit.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

Scheme 35

1. Different threads for switch on high pressure and low pressure sides.
2. Only valves and O-rings that are resistant to refrigerant R134a and refrigerant oil must be installed.

A - Connection (soldered in)

B - O-ring

C - Valve (with O-ring)

Scheme 36

This programmer switches the refrigerant flow direction through the 2nd evaporator if the temperature on the cooling fins on the 2nd evaporator lowers to the freezing point for water (icing protection).

RADIATOR FAN CONTROL MODULE -J293

Note. There are different construction styles.

This control module switches on and off the A/C clutch and therefore the A/C compressor. It switches the coolant fan and calculates the pressure in the refrigerant circuit on vehicles with a High pressure sensor -G65- or A/C pressure/temperature sensor -G395-.

Scheme 37

Note. Available in different construction styles, some separate some installed on radiator fan -arrows-.

This control module switches on and off the A/C clutch and therefore the A/C compressor. It switches the coolant fan and calculates the pressure in the refrigerant circuit on vehicles with a high pressure sensor -G65- or A/C pressure/temperature sensor -G395-.

Scheme 38

Scheme 39

Function

The A/C Evaporator Temperature Switch -E33- determines the temperature between the evaporator cooling fans. It prevents the possibility of ice building up between the evaporator cooling fans because the current entry to the condenser magnetic clutch is interrupted when the temperature on the cooling fins lowers to the freezing point for humidity.

The insertion depth of the feeler tube is marked or indicated in the repair information. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

Note. Installed in VW vehicles with A/C compressor drive via ribbed belt.

Scheme 40

Function

The Evaporator Vent Temperature Sensor -G263- or Evaporator Temperature Sensor -G308- determines the temperature behind the evaporator. This value goes to the air conditioning control module and serves as a reference signal for regulating the A/C compressor. This prevents the evaporator from icing up.

A/C SYSTEM, OPERATING AFTER CHARGING

Note. If A/C compressor was removed, it must be cranked by hand at ribbed belt pulley/freewheel approximately 10 rotations before bringing into operation for the first time. This prevents damage in the A/C compressor due to liquid when switching the A/C system on. If there is oil in the A/C compressor cylinder, it will be forced out.

Start engine with compressor switched off (version with A/C clutch).

Scheme 41

Set compressor to minimum output, for example, "Econ" or A/C off mode (version with no A/C clutch with regulating valve).

Wait until idle speed has stabilized.

Switch on compressor and operate system for at least 2 minutes at idling speed.

If necessary, check pressures in refrigerant circuit using A/C service station.

Turn engine off.

Screw out handwheel on quick-release coupling adapter.

Disconnect charging hose from refrigerant circuit.

Screw protective caps back on.

REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION

1. The refrigerant circuit is to be discharged if parts of the refrigerant circuit are to be removed, if there is any doubt about the quantity of refrigerant in the circuit or if safety precautions so require.
2. The work procedure is always to be performed as described in the operating instructions for the A/C service station.
3. The procedure described here is for the A/C service station -ROB 134APF-.

Before filling the refrigerant circuit with refrigerant, it should be evacuated (vacuum) for 45 minutes on systems with 1 evaporator and 60 minutes on systems with 2 evaporators. Moisture is also extracted from the circuit.

Leaks may be found when evacuating the refrigerant circuit.

Evacuating

Note. There is a possibility of refrigerant oil being extracted from the refrigerant circuit together with the refrigerant. To ensure compressor lubrication, the refrigerant oil in the circuit must be topped up with fresh oil. Refer to MAINTENANCE, DIAGNOSIS . On vehicles with an A/C compressor without a magnetic clutch (with A/C compressor regulator valve -N280-), the engine should run < 10 minutes with the refrigerant circuit empty and closed (the A/C compressor also runs continuously). Engine speed must not exceed 2000 RPM. On vehicles equipped with an A/C compressor with A/C clutch, the engine must be started since the A/C Pressure Switch -F129- or High Pressure Sensor -G65- (checks whether refrigerant is present in the circuit) switches off the A/C clutch as soon as there is no refrigerant in the refrigerant circuit.

Switch off the ignition.

Check refrigerant oil quantity in refrigerant circuit if necessary. Refer to MAINTENANCE, DIAGNOSIS .

Connect service station to power supply.

Check quantity of refrigerant in the A/C service station.

Connect charging hose of A/C service station to vehicle refrigerant circuit with quick-release coupling adapter (refer to vehicle-specific refrigerant circuit). Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Only tighten the handwheel on the quick-release coupling adapter just enough so the valves in the service connections are securely open. Do not put too much pressure on the valve.

Note. If pressure is to be measured after charging system on vehicles with a service connection on one side of the refrigerant circuit only, use valve adapter and charging hose with valve opener.

Initiate vacuum phase on the A/C service station. The refrigerant circuit is automatically evacuated. Check the preset evacuating time if necessary.

When the vacuum phase ends, the refrigerant circuit leak test begins. Pressure in bar and seconds are displayed.

Proceed as follows if the vacuum is not maintained

Start the vacuum phase on the A/C service station again. The refrigerant circuit is automatically evacuated. Check the preset evacuating time if necessary. Watch the vacuum indicator for an extended period of time. Only when the vacuum is maintained can the refrigerant circuit be charged.

1. If there is a leak that allowed enough air to enter during evacuation that the A/C service station cannot generate a sufficient vacuum or that the vacuum is lost immediately after switching the A/C service station off

Determine the location of the leak in the refrigerant circuit as follows, refer to LEAK DETECTION .

REFRIGERANT CIRCUIT, CHARGING WITH SERVICE STATION

1. The work procedure is always to be performed as described in the operating instructions for the A/C service station.
2. Before pouring in refrigerant, correct the quantity of refrigerant oil. «[For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation»(ref-475571-S07865064812012052300000) .
3. The entire refrigerant charge can be added to either the high or low pressure side.

Charging the refrigerant circuit

Switch off the ignition.

Discharging refrigerant circuit using service station. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION .

Screw out handwheel at quick-release coupling adapter (to close it).

Allow refrigerant to flow into charging hose.

Tighten the handwheel on the quick-release coupling adapter without putting too much pressure on the valve and add the specified amount of refrigerant.

Switch off service station.

Note. If A/C compressor was removed, it must be cranked by hand at ribbed belt pulley/freewheel approximately 10 rotations before bringing into operation for the first time. This prevents damage in the A/C compressor due to liquid when switching the A/C system on. If there is oil in the A/C compressor cylinder, it will be forced out.

Start engine with compressor switched off (version with A/C clutch).

Set compressor to minimum output, for example, "Econ" or A/C off mode (version with no A/C clutch with regulating valve).

Wait until idle speed has stabilized.

Switch on compressor and operate system for at least 2 minutes at idling speed.

If necessary, check pressures in refrigerant circuit using A/C service station.

Turn engine off.

Screw out handwheel on quick-release coupling adapter.

Disconnect charging hose from refrigerant circuit.

Screw protective caps back on.

REFRIGERANT, TRANSFERRING TO A/C SERVICE STATION CHARGING CYLINDER

1. The work procedure is always to be performed as described in the operating instructions for the A/C service station.
2. A certain quantity of refrigerant is specified as charge for each air conditioning system. To ensure that the correct amount of refrigerant is added and the cooling output is not reduced, the charging cylinder stands on a scale indicating the weight.

SERVICE STATION, IMPORTANT USAGE INFORMATION

Note. The chemical materials (stop leak additive) for sealing leaks in the refrigerant circuit offered on the market are not approved by VW Audi AG. There are no permanent, validity or material compatibility tests. Therefore damage or malfunctions in the A/C system or the A/C Service Station cannot be excluded. The stop leak additives offered on the open market have different physical and chemical properties, which can impair the function of the A/C system and the A/C Service Station and can even shut down the system completely. VW does not approve the use of chemicals to seal leaks in the refrigerant circuit. Chemicals used to seal leaks in the refrigerant circuit often react with air and the moisture in it. They cause deposits in the refrigerant circuit and the A/C service station and malfunctions in valves and other components that they come in contact with. These deposits cannot be removed completely from the components. Chemicals used to seal leaks in the refrigerant circuit usually cannot be detected from outside. The label that should be applied to identify it is often missing. Therefore be careful when working with if you do not know its service history. Accessories offer containers used to separate out these chemicals (used to seal leaks in the refrigerant circuit). Because VW does not approve the use of these chemicals, there is no evidence of the effectiveness of these filters.

Note the following when operating an A/C service station

1. The filters and dryers installed must be replaced at the latest on completion of the service life specified in the relevant operating instructions.
2. Only refrigerant oils that are approved for the refrigerant circuit in that vehicle may be added.

Extracted refrigerant must not be reused under the following conditions, even after cleaning in the station

1. In the case of A/C compressor damage in which the refrigerant was disintegrated due to overheating.
2. In the case of dark, sticky deposits in the refrigerant circuit (these can only be found after opening the system).
3. If there is any doubt as to the composition of the refrigerant extracted from the refrigerant circuit.

The A/C service station is to be drained in all these cases, the system cleaned if necessary and the filters, dryers and refrigerant oil replaced.

For example, within Germany, contaminated refrigerant can be returned to the supplier in recycling containers for recycling or for environmentally safe disposal. Other or additional regulations may apply in other countries.

Commercially available service stations can be classified in 2 groups

1. A. A/C service stations which clean extracted refrigerant for reuse (extraction and recycling stations) such as the A/C service station -ROB 134APF-.

1. B. A/C service stations which transfer extracted refrigerant to recycling containers (for large-scale recycling). These are referred to as extraction systems.

PRESSURE GAUGE, TESTS AND MEASUREMENTS

Indicators on pressure gauge

Scheme 42

1. Temperature scale for refrigerant R134a CF3-CH2F or CH2F-CF3.
2. Pressure scale

The pressure gauge may have one or more temperature scales next to the pressure scale. R134a scale values are allocated respectively in the vapor pressure table. Since various refrigerants create different vapor pressures at the same temperature, each temperature scale is identified for the respective refrigerant.

a- Pressure And Temperature Measurement At Refrigerant Circuit

1. High pressure gauge measures pressure and temperature, which expand uniformly from outlet of A/C compressor via the condenser up to constriction (restrictor, or expansion valve) with A/C system switched on.
2. Low pressure gauge measures pressure and temperature, which expand uniformly from constriction (restrictor, or expansion valve) via evaporator up to input of A/C compressor with A/C system switched on.

Note. The relationship between pressure and temperature indicated on the gauges only exists in a refrigerant circuit that contains liquid or vapor, but not gas. In a gaseous state, the temperature is approximately 10°C (50°F) to 30°C (86°F) higher than indicated on the gauge.

b - Verification Of Refrigerant In A Closed Vessel

Refrigerant R134a is present in a closed vessel or in a refrigerant circuit when the temperature indicator on the gauge matches the refrigerant temperature (the temperature of standing fluid is equal to the outside temperature).

A closed vessel or a refrigerant circuit that has been switched off is empty when the temperature indicated on the gauge is below the temperature of the refrigerant.

Note. The relationship between pressure and temperature indicated on the gauges no longer applies if no liquid is present and the pressure is built up solely by gas.

DETECTING LEAKS

Note. This repair information describes different methods for detecting leaks in the refrigerant circuit. These methods have been tested and result in success when used correctly. If when searching for compressed air/Nitrogen or vacuum leaks none are found, add a leak detection additive i.e UV leak detection additive, to the electric leak detecting unit. Minor leaks can be detected using an electronic leak detector or UV leak detector lamp. Many methods for detecting leaks in the refrigerant circuit are offered in the open market. These methods do not always have optimum results. If they are not used exactly according to specifications, they can indicate refrigerant circuit components have leaks even when they do not. Also, refrigerant circuit components can be damaged by some methods. Do not repair components with leaks. Replace them with new original parts. Do not charge a leaking refrigerant circuit with refrigerant. Evacuate the circuit and check it for leaks before charging. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION .

Note. VW does not approve the use of chemicals to seal leaks in the refrigerant circuit. Chemicals used to seal leaks in the refrigerant circuit often react with air and the moisture in it. They cause deposits in the refrigerant circuit and the A/C service station and malfunctions in valves and other components that they come in contact with. These deposits cannot be removed completely from the components, even by flushing. Chemicals used to seal leaks in the refrigerant circuit usually cannot be detected from outside. The label that should be applied to identify it is often missing. Therefore be careful when working with if you do not know its service history. Accessories offer containers used to separate out these chemicals (used to seal leaks in the refrigerant circuit). Because VW does not approve the use of these chemicals, there is no evidence of the effectiveness of these filters.

SEARCHING FOR REFRIGERANT CIRCUIT LEAKS WITH COMPRESSED AIR OR NITROGEN

Note. A leak can be identified if a maximum of pressure of 15 bar can be generated in the refrigerant circuit using clean, dry compressed air or nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN . If the leak is large enough, the sound of escaping air or gas can be heard at the location of the leak. Use the service connection for the compressed air or nitrogen. The quick-release coupling adapter for service connections can be connected to the air compressor using a modified filler hose -A- (for example, with 5/8" 18 UNF threads, different from the threads on the quick-release coupling adapter) and a suitable adapter -B-. Refer to IMPROVISED TOOLS . This keeps humidity, oil and dirt coming out of the workshop compressed air system from getting into the A/C refrigerant circuit. Also use a combination fine-gauge filter for compressed air systems such as those that are standard in paint shops. Install it between the compressed air system and the filler hose -A-. A compressed gas cylinder filled with nitrogen -3- can be connected to the closed refrigerant circuit using a pressure gauge battery with a pressure reducer for nitrogen (maximum reduction pressure: 15 bar) -1- and a filler hose -2- (for example, with 5/8" 18 UNF threads) connected to the service connection. A quick-release coupling adapter must also be connected to the service connection. Refer to IMPROVISED TOOLS .

Slowly increase the pressure in the refrigerant circuit to a maximum of 15 bar.

Find the location of the leak by listening for the sound of venting gas. An Ultrasonic tester -V.A.G 1842- will aid in detecting the origin of noise.

Use clean, dry compressed air to force the nitrogen out of the refrigerant circuit. The nitrogen must not get into the Service bottle. Reason: gases that do not condense do not get into the Service bottle.

Repair the leak.

Evacuate and again observe the vacuum display over a period of hours. Only when the vacuum is maintained can the refrigerant circuit be charged.

1. If there is a leak that is small enough that no air or very little air vents through it and the A/C service station can generate a sufficient vacuum: The vacuum indicator does not increase after switching the A/C system service station or only increases slowly, indicating that air is only entering through a small leak.

Add 100 grams of refrigerant to the circuit, find the location of the leak using an electronic leak detector and repair it. Refer to REFRIGERANT CIRCUIT, FINDING LEAKS WITH ELECTRONIC LEAK DETECTOR VAG 1796 or add UV contrast dye to the refrigerant and find the location of the leak with the leak detection system VAS 6201 and repair it. Refer to REFRIGERANT CIRCUIT, FINDING LEAKS WITH LEAK DETECTION SYSTEM VAS 6201 OR VAS 6196 .

Empty the refrigerant circuit, if necessary. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION .

Evacuate and check the vacuum display again over several hours. Only when the vacuum is maintained can the refrigerant circuit be charged.

REFRIGERANT CIRCUIT, FINDING LEAKS WITH ELECTRONIC LEAK DETECTOR VAG 1796

Note. Minor leaks can be detected using an electronic leak detector for example.

Evacuate the refrigerant circuit with the A/C service station. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION .

Note. Be ready to evacuate a large leak should one be found. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION . If no leak is found during evacuation or there is a leak that is so small that the location cannot be found, proceed as follows. Refer to SEARCHING FOR REFRIGERANT CIRCUIT LEAKS WITH COMPRESSED AIR OR NITROGEN . Currents of air quickly disperse refrigerant gas. Draughts must therefore be avoided during leak detection. If the refrigerant circuit is completely empty, fill with refrigerant to approximately 10% of the fill capacity (R134a label or vehicle-specific Repair Information).

Leak Detection

Start up leak detector in line with relevant operating instructions.

Always hold test probe beneath suspected leak.

Depending on the model, leak detection is indicated by an increase in clicking rate or a warning tone (refer to operating instructions for leak detector).

Scheme 43

REFRIGERANT CIRCUIT, FINDING LEAKS WITH LEAK DETECTION SYSTEM VAS 6201 OR VAS 6196

Special tools and workshop equipment required

1. Leak Detection System -VAS 6196
2. Leak Detection System -VAS 6201

Note. Small leaks can be detected using a UV-leak detection additive for example.

Evacuate the refrigerant circuit with the A/C service station. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION .

Note. Be ready to evacuate a large leak should one be found. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION . If no leak is found during evacuation or there is a leak that is so small that the location cannot be found, proceed as follows. Refer to SEARCHING FOR REFRIGERANT CIRCUIT LEAKS WITH COMPRESSED AIR OR NITROGEN . Currents of air quickly disperse refrigerant gas. Draughts must therefore be avoided during leak detection. If the refrigerant circuit is completely empty, fill with refrigerant to approximately 10% of the fill capacity (R134a label or vehicle-specific Repair Information).

Scheme 44

The cartridge -A- contains 15.4 ml leak detection additive (one unit -B- corresponds to 2.5 ml).

Assemble hand pump -VAS 6201-item -1- with cartridge item -2- -VAS 6201/2-.

Scheme 45

Insert the filler tube -VAS 6201/8- in the hand pump.

Open hand pump service valve.

Leak detection additive is best added to empty refrigerant circuit via opened connection.

Scheme 46

Open an easily accessible connection point on refrigerant circuit

Cover area around connection point with foil or absorbent paper.

Hold tube upwards.

Tighten the toggle on the hand pump until the leak detection additive comes out of the tube.

Add 2.5 +/- 0.5 ml (milliliter = cm 3 ) of leak detection additive to the refrigerant circuit.

Note. If leak detection fluid was filled already in a refrigerant circuit for an earlier repair, note the following: only add new leak detection additive if the refrigerant oil will be replaced. If only a portion of the refrigerant oil was replaced, only add a proportionate amount of the leak detection additive. For example, if 100 ml of refrigerant oil was replaced in a vehicle with 250 ml, add only 1 ml (cm 3 ) of leak detection additive.

Replace the O-rings on opened connection point.

Assemble refrigerant circuit.

Apply a label near the service connection stating that leak detection additive was added to the refrigerant circuit.

Evacuate and recharge refrigerant circuit according to specification. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH SERVICE STATION and REFRIGERANT CIRCUIT, CHARGING WITH SERVICE STATION .

Start the A/C system.

Note. The A/C system must run for at least 60 minutes so the additive distributes itself through the entire refrigerant circuit. The compressor must be running. Depending on the size of the leak, it may become visible within that time.

Find the leak in the refrigerant circuit with the UV lamp -VAS 6196/4-. Refer to Detecting leaks in refrigerant circuit using UV lamp VAS 6196/4 .

Leak Detection Additive With Filled Refrigerant Circuit, Filling

Note. If leak detection fluid was filled already in a refrigerant circuit for an earlier repair, note the following: only add new leak detection additive if the refrigerant oil will be replaced. If only a portion of the refrigerant oil was replaced, only add a proportionate amount of the leak detection additive. For example, if 100 ml of refrigerant oil was replaced in a vehicle with 250 ml, add only 1 ml (cm 3 ) of leak detection additive. A small quantity of leak detection additive remains in the service connection. Carefully remove this residual amount so a leaking area is not detected erroneously upon a later leak detection.

The cartridge -A- contains 15.4 leak detection additive (one unit -B- corresponds to 2.5 ml).

Switch off ignition.

Remove sealing cap from service connection of low pressure side in refrigerant circuit.

Assemble hand pump -VAS 6201- item -1- with cartridge item -2- -VAS 6201/2-.

Note. Make sure the hand pump hose is completely filled with leak detection additive.

Place the quick-release coupling on the low pressure side service connection and tighten the hand wheel to open the service coupling. Hold the hose upward and tighten the handle of the hand pump just enough until the leak detection additive starts to emerge from the tube.

Cover area around service connection on vehicle with foil or absorbent paper.

Scheme 47

Tighten the toggle on the hand pump to add 2.5 +/- 0.5 ml (milliliter = cm 3 ) of leak detection additive to the refrigerant circuit.

Close the service coupling and remove it from the service connection.

Scheme 48

Remove the rest of the leak detection additive from the service connection, for example with absorbent paper.

Seal service connection with sealing cap.

If necessary, clean area around service connection using cleaning agents.

Place a label next to the service connection stating that leak detection additive was added to the refrigerant circuit.

Start the A/C system.

Note. The A/C system must run for at least 60 minutes so the additive distributes itself through the entire refrigerant circuit. The compressor must be running. Depending on the size of the leak, it may become visible within that time.

Find the leak in the refrigerant circuit with the UV lamp -VAS 6196/4-. Refer to Detecting leaks in refrigerant circuit using UV lamp VAS 6196/4

Detecting leaks in refrigerant circuit using UV lamp VAS 6196/4

Note. The A/C system must run for at least 60 minutes so the additive distributes itself through the entire refrigerant circuit. The compressor must be running. Depending on the size of the leak, it may become visible within that time. With leaks on evaporator, leak detection additive is possibly washed off with condensation and flows out via evaporator drain. Since the evaporator is not easily accessible on most vehicles, checking the evaporator drain may indicate if the evaporator is leaking. However, it is necessary for this purpose that leak detection additive has already been in the refrigerant circuit for a long period of time. Protective goggles do not only serve as eye protection but also amplify the illumination of leak detection additive under UV light. Depending on the accessibility of different components in the refrigerant circuit, it may be necessary to remove some vehicle components such as the bumper or air filter.

Move vehicle into a slightly darker area of the workshop (with daylight or bright lighting the effect of the UV light is diminished).

Scheme 49

Check the accessibility of the various components in the refrigerant circuit and remove any components in the area that block access to the refrigerant circuit such as noise insulation and the bumper.

Wear protective eyewear to protect the eyes.

Connect the UV-lamp to a 12 volt battery (vehicle battery). Observe correct polarity of connections.

Switch on UV lamp and illuminate components of refrigerant circuit. Locations where refrigerant, refrigerant oil and leak detection additive has leaked out light up under fluorescent UV light.

Note. The leak detection additive can remain in the refrigerant circuit.

REFRIGERANT CIRCUIT CONCERNS

Note. The air conditioning system is functioning correctly when the air flowing from the instrument panel vents has a temperature of 7°C or lower. Setting on Climatronic "LO". Setting on air conditioning system "AC" on; "max" ; "cold".

1. The A/C system OBD cannot find malfunctions with the Vehicle Diagnostic Tester in "Guided Fault Finding". The measured value block does not show any shut-off condition for the A/C compressor (only on vehicles with "A/C system" OBD).

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Diagnosis and Testing .

Note. With all complaints marked with *, refer to PRESSURES, CHECKING .

1. Total cooling system failure.*
2. Insufficient cooling performance at all vehicles speeds or engine speeds.*
3. None or insufficient cooling after driving a few miles.* *
4. A/C compressor, A/C Clutch -N25- or A/C Compressor Regulator Valve -N280- are switched off by A/C Refrigerant Low Pressure Switch -F73-, A/C Refrigerant High Pressure Switch -F118-, A/C Pressure Switch -F129- or by A/C Control Head -E87- or Climatronic Control Module -J255- due to excessive or insufficient pressure. *
5. None or sharp decrease in fresh-air supply after driving several miles (evaporator iced up).* *

From these, the following complaints may also occur

The A/C compressor makes noises

Re-tighten compressor securing bolts and compressor bracket using a torque wrench.

Check routing of refrigerant lines; they must not touch other components and must not be subject to strain (align if necessary).

Noise (refrigerant hammer) occurring immediately after switching on air conditioner and/or when cornering or braking

Discharge, evacuate and charge refrigerant circuit (too much refrigerant in circuit).

Note. Too much refrigerant oil in the circuit could also cause this problem. This could occur if the amount of refrigerant oil was not adjusted when replacing the A/C compressor. If this occurs, flush the refrigerant circuit with refrigerant R134a. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A . Drain refrigerant from the A/C compressor using the oil drain plug. To facilitate this, the ribbed belt pulley or magnetic clutch plate on the A/C compressor should be rotated by hand. After flushing, the entire quantity of refrigerant oil specified by MAINTENANCE, DIAGNOSIS should be added to the refrigerant circuit (50 grams directly in the A/C compressor).

Water sprays out of vents (in dash panel or footwell) although air conditioning system is otherwise functioning properly

Check proper routing of condensate drain; it must not be crushed or kinked.

Check condensation drain valve, it must not be clogged by wax or underbody sealant and must open and close properly.

Check plenum chamber cover; it must not be damaged and must be properly installed (to stop water running into evaporator).

Check water drains in plenum chamber; they must not be blocked (for example, by leaves).

ODOR FROM EVAPORATOR OR HEAT EXCHANGER

1. Fishy smell

From leak at cooling system of engine or of A/C system heater core.

Note. If the fishy smell gets weaker when the temperature is set to cold and stronger when it is set to warm, then check the heat exchanger for leaks.

1. Smells like a burned clutch.
2. Evaporation from floor mats, decorative seat covers, etc.
3. Musty smell

Due to various contaminants, such as leaves, pine needles, etc. collecting.

Note. Clean the plenum chamber.

Due to water that cannot drain out of the plenum chamber.

Note. Check that the plenum chamber water is draining.

1. Odor from the Heater and A/C Unit

Note. Odors originating in the heating and A/C unit can mainly be detected in fresh air mode and recirculated air mode.

Due to too much condensation water in A/C unit.

Note. Check the condensation water drain. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Diagnosis and Testing .

Due to an old or heavily contaminated dust and pollen filter.

Note. Check the dust and pollen filter. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Due to deposits on evaporator fins.

Note. Clean the evaporator using an Ultrasound A/C Cleaner -VAS 6189A- or pressure cup gun -V.A.G 1538- and a suitable spray nozzle. Refer to ULTRASOUND A/C CLEANER VAS 6189A and EVAPORATOR, SPRAYING WITH PRESSURE CUP GUN AND SPRAY NOZZLE VAG 1538 .

PRESSURES, CHECKING

Switch off the ignition.

Connecting service station, refer to SERVICING STATION, CONNECTING FOR MEASURING AND TESTING .

Take pressure gauge readings (two possible results).

Note. Temperature of refrigerant circuit components should be equal to ambient temperature. Pressure will deviate from values in table if individual components of refrigerant circuit are warmer or colder. At absolute pressure, 0 bar corresponds to absolute vacuum. Normal ambient pressure (positive pressure) corresponds to 1 bar absolute pressure. 0 pressure corresponds to an absolute pressure of one bar on most pressure gauges (indicated by -1 bar below 0). On vehicles with High Pressure Sensor -G65- with which the measured pressure is displayed in the measured value block, the measured pressure should correspond to the values in the table.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Pressure in refrigerant circuit lower than indicated in table

Not enough refrigerant in refrigerant circuit.

Determine refrigerant circuit leaks. Refer to REFRIGERANT CIRCUIT, FINDING LEAKS WITH ELECTRONIC LEAK DETECTOR VAG 1796 .

Check pressure relief valve.

If pressure relief valve has responded

Check coolant fan activation.

Check refrigerant lines and hoses for cross-section constrictions caused by inadequate bending radii.

Check refrigerant pipes and hoses for external damage.

If no malfunction is found, flush refrigerant circuit with compressed air and nitrogen.

Pressure in refrigerant circuit in line with table or higher

Start the engine.

Set air conditioning system to maximum cooling output.

Note. If the low pressure switch was removed to connect the service station, bridge the electrical connections in the corresponding connector for the pressure measurement.

1. A/C compressor is driven by the engine via A/C Clutch -N25-.
2. The A/C Compressor Regulator Valve -N280- is activated by the Climatronic Control Module -J255-.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation

If compressor is not driven with engine running or regulating valve is not actuated

Determine and eliminate cause for example, by checking air conditioner DTC memory.

Observe test conditions.

Check the A/C clutch -N25- voltage supply. If it is OK, repair the A/C clutch.

Check activation of A/C Compressor Regulator Valve -N280-. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

1. Check on vehicles with restrictor and reservoir (with internally regulated A/C compressor). Refer to «CHECKING WITH RESTRICTOR AND RESERVOIR WITH INTERNALLY REGULATED A/C COMPRESSOR»(ref-475566-S01241940192012052300000) .
2. Check on vehicles with expansion valve and reservoir (with internally regulated A/C compressor). Refer to «CHECKING WITH EXPANSION VALVE AND RESERVOIR WITH INTERNALLY REGULATED A/C COMPRESSOR»(ref-475566-S32861714862012052300000) .
3. On vehicles with expansion valve and reservoir (without regulated A/C compressor). Refer to «CHECKING WITH EXPANSION VALVE AND RESERVOIR WITHOUT REGULATED A/C COMPRESSOR»(ref-475566-S39106268722012052300000) .
4. Checking pressures for vehicles with restrictor, reservoir and A/C Compressor Regulator Valve -N280- (externally regulated A/C compressor). Refer to «CHECKING WITH RESTRICTOR, RESERVOIR AND A/C COMPRESSOR REGULATOR VALVE N280»(ref-475566-S22322770702012052300000) .

CHECKING WITH RESTRICTOR AND RESERVOIR WITH INTERNALLY REGULATED A/C COMPRESSOR

Note. Connecting service station, refer to SERVICING STATION, CONNECTING FOR MEASURING AND TESTING . Observe test requirements, refer to PRESSURES, CHECKING .

Bring engine speed up to 2000 RPM.

Check the pressure gauge on the A/C service station.

Note. Switching pressures for refrigerant circuit switches are vehicle-specific. Connection with valve for low-pressure switch or at evaporator is only to be used for vehicles with no service connection on low-pressure side and inaccessible connection at compressor or accumulator (measurement accuracy). Only applies to certain vehicles.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Target values

High-pressure side

Increasing from initial pressure (when connecting pressure gauges) to a maximum of 20 bar.

Low-pressure side

Decreasing from initial pressure (when connecting pressure gauges) to the value in the graph.

Scheme 50

A - High pressure (measured at service connection) in bar

B - Low pressure (measured at connection with valve at compressor or accumulator) in bar

C - Permissible tolerance range

D - Low pressure (measured at connection with valve for low-pressure switch or at service connection) in bar

E - Permissible tolerance range

Note. If no malfunction is found with this complaint, flush (clean) refrigerant circuit with refrigerant R134a. If that is not possible in this workshop, flush the refrigerant circuit with compressed air and remove moisture with nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A and REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN .

Note. For the malfunction "high pressure normal, low pressure too low", note the following: This fault may cause the evaporator to ice up or the A/C Refrigerant Low Pressure Switch -F73- to shut off the compressor although the amount of refrigerant in the circuit is OK.

Note. Overfilling with refrigerant oil can occur in the event, for example, the compressor has been replaced without adjusting the quantity of refrigerant oil. If the A/C compressor is not replaced, the refrigerant oil should be drained from the A/C compressor via the oil drain plug. Out of the entire quantity of refrigerant oil, 50 grams should be put in the A/C compressor and the rest in the refrigerant circuit. MAINTENANCE, DIAGNOSIS

CHECKING WITH EXPANSION VALVE AND RESERVOIR WITH INTERNALLY REGULATED A/C COMPRESSOR

Note. Connecting service station, refer to SERVICING STATION, CONNECTING FOR MEASURING AND TESTING . Observe test requirements, refer to PRESSURES, CHECKING .

Bring engine speed up to 2000 RPM.

Observe manometer battery.

Note. Switching pressures and design of refrigerant circuit switches are vehicle-specific.

The pressures should be measured at the service connections. The location of these connections is vehicle-specific.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation

Target values

High-pressure side

Increasing from initial pressure (when connecting pressure gauges) to a maximum of 20 bar.

Low-pressure side

Decreasing from initial pressure (when connecting pressure gauges) to the value in the graph.

Scheme 51

A - High pressure in bar

B - Low pressure in bar

C - Permissible tolerance range

Note. If no malfunction can be found and the function of the A/C system is not correct after repeating the test, flush (clean) refrigerant circuit with refrigerant R134a. If that is not possible in this workshop, flush the refrigerant circuit with compressed air and remove moisture with nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A and REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN .

Note. If the function is not correct after flushing the refrigerant circuit, the expansion valve must be replaced.

Note. Always replace reservoir in case of this malfunction.

Note. If the function of the A/C system is not correct when the test is repeated, re-install old expansion valve and flush refrigerant circuit with compressed air and nitrogen. Then replace A/C compressor and reservoir.

Note. If A/C system function is not OK when the test is repeated, flush (clean) refrigerant circuit. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A . Then replace A/C compressor and reservoir. With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK.

Note. Overfilling with refrigerant oil can occur in the event, for example, the compressor has been replaced without adjusting the quantity of refrigerant oil. If the A/C compressor is not replaced, the refrigerant oil should be drained from the A/C compressor via the oil drain plug. Out of the entire quantity of refrigerant oil MAINTENANCE, DIAGNOSIS , 50 grams should be put in the A/C compressor and the rest in the refrigerant circuit.

CHECKING WITH EXPANSION VALVE AND RESERVOIR WITHOUT REGULATED A/C COMPRESSOR

Test Prerequisites

1. Radiator and condenser are clean (clean if necessary).
2. The ribbed belt for the A/C compressor and alternator tensioned correctly.
3. All air ducts, covers and seals are OK and installed correctly.
4. The doors reach their end position.
5. Engine is warm.
6. Evaporator and heater not drawing in secondary air (at maximum fresh-air blower speed).

With engine running and A/C system set to maximum cooling output, pay attention to the following points

1. The fresh air blower is running.
2. The coolant fan must be running or it must be switched on.
3. The recirculation/fresh air door must be in the "recirculation" position.
4. Ambient temperature is greater than 15 0 C.
5. The A/C Evaporator Temperature Switch -E33- is installed correctly and its switch temperatures are correct.

Checking

Switch off the ignition.

Connect pressure gauge set (A/C service station).

Take pressure gauge readings. There are two possible results A and B.

1. A- The pressure in the refrigerant circuit is lower than the pressure specified in the table. There is not enough refrigerant in the circuit.

Search for leak with leak detection device.

The pressure release valve is open, check coolant fan activation according to the wiring diagram.

Check refrigerant pipes and hoses to see if they are bent too sharply (cross-section constrictions) or have external damage. If no malfunction is found, flush refrigerant circuit.

1. B - The pressure in the refrigerant circuit matches the table or is higher.

Start the engine.

Set A/C system to maximum cooling output.

Open doors.

Open vents in instrument panel.

The A/C compressor is driven by the engine via the magnetic clutch using the ribbed belt.

Note. If the A/C compressor is not driven, check A/C Clutch -N25- voltage supply. If the voltage supply is OK, repair the magnetic clutch.

If the A/C compressor is driven, check refrigerant circuit

Bring engine speed up to 2000 RPM.

Observe manometer battery

Specified Values

High-pressure side

Increasing from pressure with engine not running to a maximum of 20 bar.

Low-pressure side

Decreasing from pressure with engine not running down to 1.3 bar.

CHECKING WITH RESTRICTOR, RESERVOIR AND A/C COMPRESSOR REGULATOR VALVE N280

Note. Connecting service station, refer to SERVICING STATION, CONNECTING FOR MEASURING AND TESTING . Observe test requirements, refer to PRESSURES, CHECKING .

Bring engine speed up to 2000 RPM.

Check the pressure gauge on the A/C service station.

Note. Switching pressures for actuation of A/C compressor regulator valve -N280- and radiator fan -V7- are vehicle-specific.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Target values

High-pressure side

Increasing from initial pressure (when connecting pressure gauges) to 20 bar.

Low-pressure side

Decreasing from initial pressure (when connecting pressure gauges) to the value in the graph.

Scheme 52

A - Low pressure (measured at service connection) in bar absolute

B - Control current for A/C Compressor Regulator Valve -N280-.

C - Permissible tolerance range

Note. Under unfavorable conditions (very high ambient temperatures, high humidity), pressure on high-pressure side may increase to max. 29 bar. The control current -B- is shown in the measured value block. The high pressure is shown in the measured value block. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Diagnosis and Testing . Low pressure settles as a function of control current for A/C compressor regulator valve -N280- within compressor output range in tolerance range. Under unfavorable conditions (very high ambient temperatures, high humidity), compressor output may not always be sufficient to attain the specified value. The specified operating current for the regulator valve must be greater than 0.3 A in order to ensure reliable valve activation. In the setting "maximum cooling output" control current is regulated to approximately 0.8 A (displayed in measured value block). Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Diagnosis and Testing . At absolute pressure, 0 bar corresponds to absolute vacuum. Normal ambient pressure corresponds to 1 bar absolute pressure. 0 pressure corresponds to an absolute pressure of one bar on most pressure gauges (indicated by -1 bar below 0).

Note. If no malfunction is found with this complaint, flush (clean) refrigerant circuit with refrigerant R134a. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A . If that is not possible in this workshop, flush the refrigerant circuit with compressed air and remove moisture with nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN .

Note. Note the following when the malfunction "high pressure normal, low pressure too low" is detected: faulty, the evaporator can ice up or the cooling output will not be reached. With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK. Check measured values of Evaporator Vent Temperature Sensor -G263- or Evaporator Temperature Sensor -G308-. Check the A/C compressor regulator valve -N280- activation

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation

Note. Overfilling with refrigerant oil can occur if, for example, the compressor has been replaced without adjusting the quantity of refrigerant oil. If the A/C compressor is not replaced, the refrigerant oil should be drained from the A/C compressor via the oil drain plug. Out of the entire quantity of refrigerant oil MAINTENANCE, DIAGNOSIS , 50 grams should be put in the A/C compressor and the rest in the refrigerant circuit.

CHECKING WITH EXPANSION VALVE, RESERVOIR AND A/C COMPRESSOR REGULATOR VALVE N280

Note. Connecting service station, refer to SERVICING STATION, CONNECTING FOR MEASURING AND TESTING . Observe test requirements, refer to PRESSURES, CHECKING .

Bring engine speed up to 2000 RPM.

Check the pressure gauge on the A/C service station.

Note. Switching pressures for actuation of A/C compressor regulator valve -N280- and radiator fan -V7- are vehicle-specific. The pressure should be measured at the service connections. The location of these connections depends on the vehicle. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Description and Operation .

Target values

High-pressure side

Increasing from initial pressure (when connecting pressure gauges) to 20 bar.

Low-pressure side

Decreasing from initial pressure (when connecting pressure gauges) to the value in the graph.

A - Low pressure (measured at service connection) in bar absolute

B - Control current for A/C Compressor Regulator Valve -N280-.

C - Permissible tolerance range

Note. Under unfavorable conditions (very high ambient temperatures, high humidity), pressure on high-pressure side may increase to max. 29 bar. The control current -B- is shown in the measured value block. The high pressure measured from the High Pressure Sensor -G65- is not shown in the measured value block. Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Diagnosis and Testing . Low pressure settles as a function of control current for A/C compressor regulator valve -N280- within compressor output range in tolerance range. Under unfavorable conditions (very high ambient temperatures, high humidity), compressor output may not always be sufficient to attain the specified value. The specified operating current for the regulator valve must be greater than 0.3 A in order to ensure reliable valve activation. In the setting "maximum cooling output" control current is regulated to approximately 0.65 A up to 0.85 A (vehicle specific, displayed in measured value block). Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Diagnosis and Testing . At absolute pressure, 0 bar corresponds to absolute vacuum. Normal ambient pressure corresponds to 1 bar absolute pressure. 0 pressure corresponds to an absolute pressure of one bar on most pressure gauges (indicated by -1 bar below 0).

Note. If no malfunction is found with this complaint, flush (clean) refrigerant circuit with refrigerant R134a. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A . If that is not possible in this workshop, flush the refrigerant circuit with compressed air and remove moisture with nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN . Check measured values from Evaporator Vent Temperature Sensor -G263- or Evaporator Temperature Sensor -G308- and activation of A/C Compressor Regulator Valve -N280-. If the measured value of the High Pressure Sensor -G65- is faulty, the evaporator can ice up or the cooling output is not reached. If the function of the air conditioning system is not OK when the test is repeated after replacing expansion valve, re-install old expansion valve and flush refrigerant circuit with compressed air and nitrogen. Then replace A/C compressor and reservoir. With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK. If expansion valve is malfunctioning (permanently closed or does not open sufficiently), A/C compressor regulator valve -N280- is actuated to maximum output and low pressure drops to value in graph or below (compressor draws off refrigerant from low-pressure side). Because refrigerant cannot flow through the expansion valve, the correct cooling output cannot be reached. The high pressure may not increase or may only increase slightly.

Note. With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK. If expansion valve is malfunctioning (permanently closed or does not open sufficiently), A/C compressor regulator valve -N280- is actuated to maximum output and low pressure drops to value in graph or below (compressor draws off refrigerant from low-pressure side). Because refrigerant cannot flow through the expansion valve, the correct cooling output cannot be reached. The high pressure may not increase or may only increase slightly.

Note. If this complaint occurs after a long operating time or only sporadically (the low pressure falls under the specified value and the evaporator ices up), replacing the dryer (installed in the reservoir) is sufficient. The quantity of refrigerant oil should be adjusted. Refrigerant circuit is then to be evacuated for at least 3 hours. First, it is not necessary to flush the refrigerant circuit with compressed air and nitrogen in case of this complaint because generally only a small amount of moisture is in the system and this can be removed by a long evacuation. With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK.

Note. Note the following when the malfunction "high pressure normal, low pressure too low" is detected: faulty, the evaporator can ice up or the cooling output will not be reached. With this malfunction, evaporator may ice up although quantity of refrigerant in circuit is OK. Check measured values from Evaporator Vent Temperature Sensor -G263- or Evaporator Temperature Sensor -G308- and activation of A/C Compressor Regulator Valve -N280-. If the measured value of the High Pressure Sensor -G65- is faulty, the evaporator can ice up or the cooling output is not reached. If the problem is with the A/C Compressor Regulator Valve -N280- (regulating valve is not actuated but compressor operates nevertheless), refrigerant circuit does not have to be flushed. With this malfunction, replacing the A/C compressor is sufficient (adjust refrigerant oil quantity in new A/C compressor). If expansion valve is malfunctioning (permanently closed or does not open sufficiently), A/C compressor regulator valve -N280- is actuated to maximum output and low pressure drops to value in graph or below (compressor draws off refrigerant from low-pressure side). Because refrigerant cannot flow through the expansion valve, the correct cooling output cannot be reached. The high pressure may not increase or may only increase slightly.

Refer to [For engine(s) BPY, CCTA, BUB, CBFA] Removal and Installation .

Note. If the problem is with the A/C Compressor Regulator Valve -N280- (regulating valve is not actuated but compressor operates nevertheless), refrigerant circuit does not have to be flushed. With this malfunction, replacing the A/C compressor is sufficient (adjust refrigerant oil quantity in new A/C compressor). Overfilling with refrigerant oil can occur if, for example, the compressor has been replaced without adjusting the quantity of refrigerant oil. If the A/C compressor is not replaced, the refrigerant oil should be drained from the A/C compressor via the oil drain plug. Out of the entire quantity of refrigerant oil MAINTENANCE, DIAGNOSIS , 50 grams should be put in the A/C compressor and the rest in the refrigerant circuit. If expansion valve is malfunctioning (permanently closed or does not open sufficiently), A/C compressor regulator valve -N280- is actuated to maximum output and low pressure drops to value in graph or below (compressor draws off refrigerant from low-pressure side). Because refrigerant cannot flow through the expansion valve, the correct cooling output cannot be reached. The high pressure may not increase or may only increase slightly.

Note. Overfilling with refrigerant oil can occur if, for example, the compressor has been replaced without adjusting the quantity of refrigerant oil. If the A/C compressor is not replaced, the refrigerant oil should be drained from the A/C compressor via the oil drain plug. Out of the entire quantity of refrigerant oil, 50 grams should be put in the A/C compressor and the rest in the refrigerant circuit. Refer to MAINTENANCE, DIAGNOSIS If expansion valve is malfunctioning (permanently open), evaporator temperature is no longer regulated such that only refrigerant in gaseous state exits from the evaporator. Under certain usage conditions, liquid droplets may then be drawn in by the compressor and cause noise (liquid cannot be compressed).

COMPRESSOR, REPLACING

Discharge refrigerant circuit

Remove A/C compressor.

Note. In the case of internal damage (on A/C compressor), flush refrigerant circuit with refrigerant R134a. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A .

Replace fluid reservoir/dryer cartridge and expansion valve or reservoir and restrictor.

If a leak is present, check the expansion valve for debris or corrosion and replace if necessary.

Assemble, evacuate and charge refrigerant circuit.

LEAKING OR DAMAGED COMPONENTS EXCEPT A/C COMPRESSOR, ACCUMULATOR OR RECEIVER

Empty Refrigerant Circuit

Remove malfunctioning component.

Remove A/C compressor.

Remove oil drain plug from A/C compressor.

Note. To speed up refrigerant oil drainage, turn A/C compressor by hand via ribbed belt or magnetic clutch plate. Pour the used refrigerator oil out of the A/C compressor. For information on handling refrigerant oil, refer to Volkswagen Service Net, Handbooks, Service Handbook; Protecting the Environment, Emissions Protection. Then fill compressor with quantity of fresh refrigerant oil corresponding to quantity of refrigerant oil in original part compressor. Refer to MAINTENANCE, DIAGNOSIS . Use different refrigerant oils and quantities for the various compressors. Refer to MAINTENANCE, DIAGNOSIS . To ensure compressor lubrication on start-up, at least 80 cm 3 of refrigerant oil must be poured into the compressor, the remainder can be added for example to the new reservoir or receiver. Refer to MAINTENANCE, DIAGNOSIS . If dirt has penetrated into the compressor with the refrigerant circuit open (for example, after an accident), compressor is to be replaced. Flush the refrigerant circuit with compressed air and remove moisture with nitrogen. Refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN .

Replace receiver or accumulator and restrictor.

Assemble, evacuate and recharge refrigerant circuit.

No Refrigerant in Circuit

Discharge refrigerant circuit.

Remove malfunctioning component, flush with compressed air, collect escaping refrigerant oil.

The new component is to be filled with the amount of refrigerant oil flushed out (plus 20 cm 3 for evaporator, plus 10 cm 3 for condenser, refrigerant pipes and refrigerant hoses) as fresh refrigerant oil fill.

Replace restrictor.

Assemble, evacuate and charge refrigerant circuit.

REPLACING RESERVOIR, NO CONTAMINANTS, NO LOSS OF REFRIGERANT

Discharge refrigerant circuit.

Replace restrictor.

Remove receiver or accumulator.

Remove dirt from receiver or reservoir.

Weigh receiver or reservoir removed.

Note. Add refrigerant oil to the reservoir until it is the same weight as the reservoir that was removed. Install new receiver or reservoir.

Assemble, evacuate and charge refrigerant circuit.

COMMERCIALLY AVAILABLE TOOLS AND MATERIALS

Note. This list outlines the testers, tools and materials required for expert refrigerant circuit repair work.

A/C Service Station -ROB 134APF- (and other A/C service stations)

1. Procedure: the operations "testing, extraction (recycling), evacuation and charging" are to be performed in line with the relevant operating instructions.
2. The filters and dryers installed are to be replaced at the latest at the end of the period of use specified in the operating instructions and whenever the station has been drained (keep replacement filter to hand. Available from equipment manufacturer, refer to operating instructions).
3. Other A/C service stations or flushing equipment that is approved by VW but not illustrated here may also be used.

Note. This A/C service station has the following known units: charging cylinder, pressure gauge set, vacuum pump, shutoff valves and charging hoses. One quick-release coupling each (for service connections on high and low-pressure side) is included in the scope of delivery of this service station.

Scheme 53

Note. With a filter -1- and two large cylindrical viewing glasses. The filter in the refrigerant circuit flushing device depends on the type and degree of contamination in the flushed refrigerant circuit, it should be changed after 2 flushing cycles at the latest. If a heavily contaminated refrigerant circuit is flushed (the refrigerant oil from the circuit is black and viscous or there are many shavings in the refrigerant circuit), the filter should be replaced after flushing.

Scheme 54

Note. With a filter -1- and one viewing glass. The filter in the refrigerant circuit flushing device depends on the type and degree of contamination in the flushed refrigerant circuit, it should be changed after 2 flushing cycles at the latest. If a heavily contaminated refrigerant circuit is flushed (the refrigerant oil from the circuit is black and viscous or there are many shavings in the refrigerant circuit), the filter should be replaced after flushing.

Scheme 55

Scheme 56

1. Hand pump with low-pressure service hose, service coupling and non-return valve -VAS 6201/1
2. Cartridge -VAS 6201/2
3. Cleaning agent -VAS 6201/3
4. UV leak detection lamp -VAS 6201/4
5. UV-absorbing safety goggles -VAS 6201/6
6. Sticker -VAS 6201/7
7. Filler tube VAS 6201/8
8. Protective gloves -VAS 6201/9

Scheme 57

Scheme 58

1. Blue 1/2 inch
2. Black 5/8 inch
3. Red 3/8 inch
4. White 3/4 inch

Scheme 59

1. Green NW 8 for the high pressure line
2. Black NW 13 for the low pressure line

Scheme 60

Scheme 61

Scheme 62

Scheme 63

1. Adapter for cleaning refrigerant circuit (flush with refrigerant R134a. Refer to «REFRIGERANT CIRCUIT, FLUSHING WITH REFRIGERANT R134A»(ref-475566-S16508585792012052300000) or blow through with compressed air and nitrogen, refer to «REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN»(ref-475566-S41211259392012052300000) .

A - 5/8" 18 UNF thread for conical seal

B - Union nut (for connection with O-ring) with thread

1. M 18x1.5 -V.A.G 1785/1
2. M 20x1.5 -V.A.G 1785/2
3. M 24x1.5 -V.A.G 1785/3
4. M 28x1.5 -V.A.G 1785/4

A - 5/8"-18 UNF thread for conical seal

B - Threaded connection for O-ring

Scheme 64

1. M 18x1.5 -V.A.G 1785/5
2. M 20x1.5 -V.A.G 1785/6
3. M 24x1.5 -V.A.G 1785/7
4. M 28x1.5 -V.A.G 1785/8

Valve Adapter

Scheme 65

A - 5/8"-18 UNF thread for conical seal

B - Internal threads with valve opener M 10x1.25 -VAG 1785/9- (for connections with valve on high pressure side) M 12x1.5 -VAG 1785/10- (for connections on low pressure side)

Note. A Schrader valve is screwed into connection -A-. A valve opener must be installed in the charging hose connection.

Scheme 66

Scheme 67

Scheme 68

5/8"-18 UNF thread

Note. Use differently colored charging hoses (1800 mm long). Have valve opener and spare seals to hand.

Scheme 69

Scheme 70

Seals can also be used for charging hoses.

Scheme 71

1. Manometer battery with pressure reducer
2. Pressure hose (inner diameter 5 mm, length 2 m) with hose fittings
3. Nitrogen cylinder
4. Hose fitting

Note. Hose fittings for connecting on Adapter Set -V.A.G 1785- with threads 5/8" 18 UNF for service connection quick-release coupling adapter to refrigerant circuit.

Scheme 72

1. High-pressure side, nominal size 16 mm
2. Low-pressure side, nominal size 13 mm

Note. This quick-release couplings are delivered with the service station.

IMPROVISED TOOLS

Scheme 73

A - Charging hose 5/8" - 18 UNF** (version with large inner diameter)

B - Compressed air system connection** (operate only with filter and dryer for compressed air)

** Commercially available tools and materials.