A/c System General Servicing Ford Econoline E350

SAFETY PRECAUTIONS

1. Always work in a well-ventilated, clean area. Refrigerant (R-12) is heavier than oxygen, and will displace oxygen in a confined area. Always wear eye protection when working around air conditioning systems and R-12. The system's high pressure can cause severe injury to eyes and skin if a hose were to burst. R-12 evaporates quickly when exposed to atmosphere, freezing anything it contacts.
2. Use care when handling refrigerant containers. DO NOT drop or strike containers or expose refrigerant containers to excessive heat. Containers must never be heated more than 125°F (52°C). Never expose R-12 directly to open flame.

USING INDIVIDUAL R-12 CANS

Disposable refrigerant cans (referred to as one pound cans) have a flat type seal or a screw type seal, and proper can tap must be used for each type. Be sure sealing gasket on can tap is in good condition. A proper safety can tap will prevent refrigerant from flowing back into open can, as tap has a one-way flow control.

Note. Recent findings by the EPA indicate that refrigerant is harmful to the Earth's protective Ozone layer. When discharging refrigerant avoid allowing refrigerant to enter the atmosphere. Refrigerant recovery system should be used when discharging the system.

MULTI-CAN DISPENSING VALVES

A multi-can dispensing valve allows attachment of several cans of refrigerant, and is a good substitute when a bulk container is not available. Cans are installed onto each leg of multi-can dispensing valve in the same manner as the individual cans, and each leg has its own can tap.

FLAT TYPE SEAL CANS

On cam-lock or one-piece can taps, first turn the handle outward to the fully open position. Securely engage locking lugs over the can flange, and lock them in place by turning cam lock or locking nut. Screw tap assembly into adapter so sealing gasket is fully seated against the can top. Turn tap inward to pierce the can and close the tap. DO NOT open tap until ready to purge the service hose or dispense refrigerant into the system.

On 2-piece can taps, be certain tap handle is turned fully inward to the closed position. Check that locking base is turned to its outer limit. Securely engage locking lugs over the can flange. Turn entire tap assembly (without disturbing the closed setting) downward into the locking base to pierce the can. DO NOT open tap until ready to dispense into system.

SCREW TYPE SEAL CANS

Ensure can tap is fully closed. Screw refrigerant can into can tap fitting until tight. This will pierce the can. Connect tap to center hose on manifold gauge set. DO NOT open tap until ready to dispense R-12 into system.

SIGHT GLASS INDICATORS

Note. Receiver-drier may be used on some models, while other models use an accumulator.

A sight glass (if used) is usually mounted in receiver-drier or in discharge line to expansion valve. Through sight glass, a visual check of refrigerant condition passing through the system can be made. There are several "indicators" that help diagnose possible problems. (Scheme 1) These "indicators" are outlined as follows

CLEAR SIGHT GLASS

A clear sight glass indicates system has correct charge of refrigerant or is excessively low on refrigerant for system circulation. Sight glass may be clear and system may contain excessive R-12. This must be verified with test gauge readings.

BUBBLY/FOAMY SIGHT GLASS

A "bubbly" or "foamy" sight glass indicates system is low on refrigerant, and air has probably entered system. However, if only occasional bubbles are noticed, during clutch cycling or system start-up, this may be a normal condition.

OIL STREAKED SIGHT GLASS

If oil streaks appear on sight glass, a lack of refrigerant may be indicated, and the system's compressor oil is circulating through the system.

CLOUDY SIGHT GLASS

A cloudy sight glass indicates desiccant contained in receiver-drier or accumulator has broken down and is being circulated through system. Sight glass readings are not necessarily positive identification of a problem. Readings should be relied upon only in conjunction with other system symptoms.

Sight Glass Indicators. Scheme 1

1992 PASSENGER CAR SERVICE VALVE LOCATIONS

1992 TRUCKS & VANS SYSTEM SERVICE VALVE LOCATIONS

STEM-TYPE VALVE OPERATION

This manually operated service valve has adjustable stem, located under a protective cap. Valve stem must be manually positioned when making gauge connections and/or reading system pressure on the gauges. (Scheme 2)

BACK-SEATED (OPERATING) POSITION

This is normal operating position, and position used for connecting and disconnecting manifold gauge set. Stem is turned fully outward to seal the service gauge port.

MID (TEST) POSITION

After service gauge manifold set has been installed (valve stem in back-seated position), turn valve stem 1 1/2 to 2 turns inward. This positions valve stem midway, allowing full system operation and permits refrigerant pressure to reach gauges.

FRONT-SEATED (OFF) POSITION

With service valve stem turned inward, valve blocks refrigerant flow through system, isolating compressor for service.

Stem-Type Service Valve Positions. Scheme 2

SCHRADER-TYPE VALVE OPERATION

Schrader valve is similar in construction and operation to a tire valve. When a test gauge hose (which has a valve core depressor) is attached, Schrader stem is pushed inward to the open position and allows system pressure to reach the gauge.

If test hose being used does not have a built-in core depressor, an adapter must be used. Never attach hoses or adapters to a Schrader valve unless it is first connected to manifold gauge set.

Note. Although similar in construction and operation to a tire valve, the Schrader-type valve cannot be replaced with a tire valve.

SPECIAL VALVE CONNECTORS

Some Ford systems use a special quick-disconnect fitting to attach a test gauge to high side service valve. This is an immediate-sealing mechanism which will prevent any accidental discharge while installing or disconnecting high side service gauge.

MANIFOLD GAUGE SET

A manifold gauge set is used to determine systems high and low side pressures, correct refrigerant charge, system diagnosis and operating efficiency. High (discharge) and low (suction) pressures must be compared to determine system operation.

LOW SIDE GAUGE

This gauge, which may have a Blue color identifying feature, is used to measure low side (suction) pressure. It reads from 0 to 150 psi (pressure scale) and from 0 to 30 inches of mercury (vacuum scale). This low side gauge is called a compound gauge because it has a dual purpose, to register either pressure or vacuum.

HIGH SIDE GAUGE

The high side gauge, which may have a Red identifying feature, is used to measure high side (discharge) pressure. It reads from 0 to 500 psi.

SCHRADER-TYPE VALVES

1. Put on safety goggles and cover vehicle's fender. Remove protective caps from Schrader valves. Do this slowly to check for leaky valves. CAUTION: Be sure hand valves on manifold gauge set are closed before connecting test hoses to Schrader valves.
2. Be sure service hoses are equipped with valve core depressor to match Schrader valve. If not, install special adapters for this purpose. Ensure both manifold gauge hand valves are closed.
3. Connect low side service hose to low side (suction) service valve. Tighten finger tight. Connect high side service hose to high side (discharge) service valve. Tighten finger tight.

STEM-TYPE VALVES

1. Put on safety goggles and cover vehicle's fender. Place valves in back-seated position. Remove protective caps from service valves. Do this slowly to check for leaky valves. CAUTION: Be sure hand valves on manifold gauge set are closed before turning service valve to the mid-position.
2. Attach low side service hose to the low side (suction) service valve. Connect high side service hose to the high side (discharge) service valve. Tighten both connectors finger tight.

Note. After test gauges are installed, you must purge test hoses of all air before proceeding with testing.

PURGING TEST HOSES

1. Be sure high and low side hoses are properly connected to service valves and all hose connections are tight.
2. If stem-type service valves are used, turn stems inward 1 1/2 to 2 turns to mid-position. Place clean shop towel over end of center service hose.
3. Now purge high side test hose by opening hand valve on the high side gauge for 3-5 seconds. This allows system's refrigerant to force air through test hoses and out center service hose into the shop towel. Immediately close high side gauge hand valve.
4. Purge low side test hose in the same manner, using hand valve of low side gauge. Close hand valve after 3-5 seconds. Purging of test hoses is complete. System is ready for testing.

STABILIZING A/C SYSTEM

1. Once manifold gauge set is attached to system, and test hoses have been purged, system is ready for testing. Place all test hoses, gauge set and other equipment away from all engine moving parts.
2. Start engine and turn air conditioner controls to maximum cooling (full cold and "MAX A/C"). Set blower fan on high speed. Open doors and/or windows and operate system for 5-10 minutes. System should now be stabilized and ready for test readings.

PRESSURE GAUGE INDICATIONS

The following typical pressure gauge indications represent conditions that may be encountered during system servicing. (Scheme 3)through (Scheme 10). Temperature and humidity, as well as other factors, affect pressure gauge readings. Pressure gauge indications should be used only as a guide.

PRESSURE GAUGE READINGS

The following typical pressure gauge indications represent conditions that may be encountered during system servicing. Temperature and humidity, as well as other factors, affect pressure gauge readings. Pressure gauge indications should be used only as a guide.

EXCESSIVE MOISTURE GAUGE READINGS

Low Side Gauge - Normal-to-Low

High Side Gauge - Normal

Other Symptoms

Sight Glass - Tiny bubbles.

Discharge Air - Becomes warm as low side cycles into vacuum. As moisture is released by saturated desiccant, it becomes released by saturated desiccant, it becomes trapped and freezes at expansion valve or orifice tube, blocking R-12 flow into the evaporator. As low side drops to a vacuum, high side may rise.

Scheme 3

Correction

1. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment.
2. Replace receiver-drier, accumulator or desiccant bag.
3. Evacuate system with vacuum pump.
4. Charge system with R-12.
5. Operate system and check performance.

DEFECTIVE THERMOSTATIC SWITCH GAUGE READINGS

Low Side Gauge - Normal

High Side Gauge - Normal

Compressor - Cycles on and off too fast.

Low Side Gauge - Not enough range shown on low side gauge.

Scheme 4

1. Stop vehicle engine and turn air conditioner "OFF".
2. Remove and discard old clutch cycling switch, install a new switch of same type.
3. Operate system and check performance.

MISADJUSTED THERMOSTATIC SWITCH GAUGE READINGS

See DEFECTIVE CLUTCH CYCLING SWITCH PRESSURE GAUGE READINGS below.

DEFECTIVE CLUTCH CYCLING SWITCH PRESSURE GAUGE READINGS

Low Side Gauge - Low-to-Normal/Normal-to-High

High Side Gauge - Normal

Compressor - Cycles at incorrect temperature or pressure.

Evaporator - May freeze and restrict airflow if switch is allowing compressor to remain on too long.

Scheme 5

Correction With Thermostatic Switch

Note. If no adjusting screw is provided, the switch is nonadjustable and must be replaced.

1. Stop engine and turn air conditioner off.
2. Remove components necessary to gain access to thermostatic adjustment screw.
3. Make certain that all wiring is positioned so that no short-circuiting can occur. Connect battery cable so that engine can be operated while making switch adjustment. Adjust thermostatic switch.

Correction With Clutch Cycling Switch

Note. Switch is non adjustable and is mounted on a Schrader valve fitting. Therefore, no system discharge is required.

1. Stop engine and turn air conditioner off.
2. Detach electrical connector from pressure sensing switch at accumulator.
3. Remove pressure sensing switch, and install a new switch.

LOW R-12 CHARGE GAUGE READINGS

Low Side Gauge - Low

High Side Gauge - Low

Discharge Air - Slightly cool.

Sight Glass - Some bubbles.

Scheme 6

1. Leak test system.
2. Discharge refrigerant from system if necessary, using approved refrigerant recovery/recycling equipment, to replace units or lines.
3. Repair leaks.
4. Check compressor oil level. System may have lost oil due to leakage.
5. Evacuate system using vacuum pump.
6. Charge system with R-12.
7. Operate system and check performance.

VERY LOW R-12 CHARGE GAUGE READINGS

Low Side Gauge - Low

High Side Gauge - Low

Discharge Air - Warm.

Sight Glass - Clear or Oil Streaks.

Compressor - Operation may have stopped if system is equipped with a refrigerant pressure sensing switch.

Scheme 7

1. If compressor operation is stopped due to a pressure sensing switch, by-pass switch with jumper wire until testing and correction are complete.
2. Add a partial refrigerant charge (to at least 50 percent system capacity), then make thorough leak test.
3. Discharge refrigerant from system using approved refrigerant recovery/recycling equipment.
4. Check compressor oil level. System may have lost oil due to leakage.
5. Evacuate system using vacuum pump.
6. Charge system with R-12.
7. Operate system and check performance.

ORIFICE TUBE PLUGGED GAUGE READINGS

Low Side Gauge - Low

High Side Gauge - Low

Discharge Air - Slightly cool.

Evaporator Inlet Pipe - Sweating or frost build up just ahead of orifice tube.

Testing

If evaporator inlet pipe after orifice tube and accumulator surface are warm, orifice tube is plugged.

1. Evacuate system using vacuum pump.
2. Replace orifice tube.
3. Charge system with R-12.
4. Operate system and check performance.

EXPANSION OR "H" VALVE STUCK CLOSED

Low Side Gauge - Low

High Side Gauge - Low

Discharge Air - Slightly cool.

Evaporator Inlet Pipe - Sweating or frost build up.

1. If evaporator inlet is cool to touch, proceed as follows: Set air conditioner for maximum cooling and operate the system. Spray liquid R-12 on head of valve or capillary tube (if equipped). Note low side gauge reading. Low side gauge should drop into a vacuum. If low side vacuum reading was obtained, warm expansion valve diaphragm chamber with hand, then repeat test step b.). If expansion valve test indicates valve operation is satisfactory, clean contact surface of evaporator outlet pipe and temperature sensing bulb. Make sure bulb is securely in contact with pipe. If expansion valve test indicates the valve is defective, discharge the system using approved refrigerant recovery/recycling equipment. Replace expansion valve, and proceed with correction procedure.
2. If expansion valve inlet shows sweating or frost proceed as follows: Discharge system using approved refrigerant recovery/recycling equipment. Disconnect inlet line at expansion valve. Remove and inspect screen. Clean and replace screen and reconnect inlet line. Proceed with correction procedure.

1. Evacuate system using vacuum pump.
2. Charge system with R-12.
3. Operate system and check performance.

EXPANSION OR "H" VALVE STUCK OPEN GAUGE READINGS

Low Side Gauge - High

High Side Gauge - High

Discharge Air - Warm

Evaporator - Sweating or frost.

Check for expansion valve stuck open, or incorrect mounting of temperature sensing bulb as follows

1. Set air conditioner for maximum cooling and operate system several minutes.
2. Spray liquid R-12 on head of valve or capillary bulb, and note low side gauge reading. It should drop into a vacuum (if not, a stuck open valve or incorrect bulb mounting is indicated). This test may not be possible on applications where sensing bulb is not accessible.
3. If low side vacuum reading is obtained, warm expansion valve diaphragm chamber with hand, then repeat test.

Scheme 8

1. If expansion valve test indicates valve operation is satisfactory, proceed as follows: Clean contact surface of evaporator outlet pipe and temperature sensing bulb, then clamp bulb securely in contact with pipe and recover with proper insulation tape. Operate system and check performance.
2. If expansion valve test indicates valve is defective, proceed as follows: Discharge system using approved refrigerant recovery/recycling equipment. Replace expansion valve, making sure all contacts are clean and secure. Evacuate system using vacuum pump, then charge system with R-12. Operate system and check performance.

COMPRESSOR MALFUNCTION GAUGE READINGS

Low Side Gauge - High

High Side Gauge - Low

Compressor - Noisy.

Scheme 9

1. Isolate compressor (if equipped with stem-type service valves) or discharge entire system using approved refrigerant recovery/recycling equipment.
2. Remove compressor cylinder head and inspect compressor. Replace reed valve plate assembly if necessary. Install cylinder head using NEW gasket.
3. Check compressor oil level.
4. Replace receiver-drier, desiccant or accumulator if: System previously opened. System operated two or more seasons with present unit. Compressor inspection revealed desiccant particles (very fine golden or brown particles).
5. Using vacuum pump, evacuate compressor or entire system (depending on procedure used in step 1).
6. Charge system with R-12.
7. Operate system and check performance.

CONDENSER MALFUNCTION OR R-12 OVERCHARGE GAUGE READINGS

Low Side Gauge - High

High Side Gauge - High

Discharge Air - Warm.

High Side Lines - Very Hot.

Sight Glass - Bubbles.

Scheme 10

1. Check electric cooling fan operation.
2. Inspect condenser for clogged air passages, bug screen, or other obstructions preventing airflow through condenser.
3. Inspect condenser mounting for proper radiator clearance. Inspect clutch type fan for proper operation. Inspect radiator pressure cap for correct type and proper operation.

After making above corrections, operate system and check performance. If condition is not corrected

1. Inspect system for overcharge of refrigerant and correct as follows: Discharge refrigerant, using approved refrigerant recovery/recycling equipment, until stream of bubbles appears in sight glass and both high and low gauge readings drop below normal. Add R-12 until bubbles disappear and pressures are normal, then add an additional 1/4-1/2 lb. of refrigerant.
2. Operate system and check performance. If Gauge Readings Still Too High Discharge system using approved refrigerant recovery/recycling equipment. Remove and inspect condenser to ensure free passage of refrigerant or replace condenser. Replace receiver-drier, desiccant bag or accumulator. Evacuate system using vacuum pump. Charge system with R-12. Operate system and check performance.

ORIFICE TUBE REPLACEMENT - AEROSTAR, BRONCO, EXPLORER

Scheme 11

Scheme 12

Scheme 13

1. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect liquid line at evaporator.
2. To disconnect liquid line, fit appropriate spring lock coupling clamp on the line. See SPRING LOCK COUPLING CLAMP table. Close clamp and push into opening side of cage to expand garter spring and release female fitting. After garter spring is expanded, pull coupling apart. (Scheme 11)
3. Pour small amount of refrigeration oil into inlet tube to lubricate orifice tube and "O" rings. Attach Orifice Tube Remover/Installer (T83L-19990-A) on the 2 tangs of the orifice tube. (Scheme 12) NOTE: DO NOT twist or rotate orifice tube in evaporator inlet tube pipe, as it may break inside the tube.
4. Hold "T" handle of orifice tube remover/installer to keep it from turning, and rotate the nut downward against inlet line until orifice tube is pulled from inlet tube. If orifice tube breaks in inlet tube, use Broken Orifice Tube Extractor (T83L-19990-B) to remove the orifice tube. (Scheme 13)
5. To remove broken orifice tube, insert screw end of extractor into inlet tube and thread into orifice tube. Rotate extractor nut downward against liquid line and remove orifice tube.
6. If only brass center tube is extracted, insert screw end of extractor into inlet. Screw end of extractor into fixed orifice tube body. Remove tube body from evaporator core line.

SPRING LOCK COUPLING CLAMP

INSTALLATION

1. Ensure replacement orifice tube is same color as that removed. Lubricate "O" rings on orifice tube with clean refrigeration oil. Place orifice tube into orifice tube remover/installer. Insert orifice tube into evaporator inlet tube until orifice tube bottoms against the stop.
2. Remove orifice tube remover/installer. Install liquid on evaporator using a new "O" ring lubricated with refrigeration oil. Pull backward on liquid line to ensure proper seating of the line. Leak test, evacuate and recharge the system. Check system for proper operation.

ORIFICE TUBE R & I - E & F SERIES, RANGER

REMOVAL

1. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect liquid line at evaporator.
2. To disconnect liquid line, fit appropriate spring lock coupling clamp on the line. See SPRING LOCK COUPLING CLAMP table. Close clamp and push into opening side of cage to expand garter spring and release female fitting. After garter spring is expanded, pull coupling apart. see scheme 16
3. Pour small amount of refrigeration oil into inlet tube to lubricate orifice tube and "O" rings. Attach Orifice Tube Remover/Installer (T83L-19990-A) on the 2 tangs of the orifice tube. see scheme 17 NOTE: DO NOT twist or rotate orifice tube in evaporator inlet tube pipe, as it may break inside the tube.
4. Hold "T" handle of orifice tube remover/installer to keep it from turning, and rotate the nut downward against inlet line until orifice tube is pulled from inlet tube. If orifice tube breaks in inlet tube, use Broken Orifice Tube Extractor (T83L-19990-B) to remove the orifice tube. see scheme 18
5. To remove broken orifice tube, insert screw end of extractor into inlet tube and thread into orifice tube. Rotate extractor nut downward against liquid line and remove orifice tube.
6. If only brass center tube is extracted, insert screw end of extractor into inlet. Screw end of extractor into fixed orifice tube body. Remove tube body from evaporator core line.

1. Ensure replacement orifice tube is same color as that removed. Lubricate "O" rings on orifice tube with clean refrigeration oil. Place orifice tube into orifice tube remover/installer. Insert orifice tube into evaporator inlet tube until orifice tube bottoms against the stop.
2. Remove orifice tube remover/installer. Install liquid on evaporator using a new "O" ring lubricated with refrigeration oil. Pull backward on liquid line to ensure proper seating of the line. Leak test, evacuate and recharge the system. Check system for proper operation.

ORIFICE TUBE R & I - CROWN VIC/GRAN MARQUIS/TWN CAR

1. Orifice tube is located in the evaporator inlet pipe. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect liquid line at evaporator.
2. To disconnect liquid line, fit appropriate spring lock coupling clamp on the line. See SPRING LOCK COUPLING CLAMP table earlier in article. Close clamp and push into opening side of cage to expand garter spring and release female fitting. After garter spring is expanded, pull coupling apart. (Scheme 11)
3. Pour small amount of refrigeration oil into inlet tube to lubricate orifice tube and "O" rings. Attach Orifice Tube Remover/Installer (T83L-19990-A) to 2 tangs on fixed orifice tube. (Scheme 12) NOTE: DO NOT twist or rotate orifice tube in evaporator inlet tube pipe, as it may break inside the tube.
4. Hold "T" handle of orifice tube remover/installer to keep it from turning, and rotate the nut downward against inlet line until orifice tube is pulled from inlet tube. If orifice tube breaks in inlet tube, use Broken Orifice Tube Extractor (T83L-19990-B) to remove the orifice tube.
5. To remove broken orifice tube, insert screw end of extractor into inlet tube and thread into orifice tube. Rotate extractor nut downward against liquid line and remove orifice tube. (Scheme 13)
6. If only brass center tube is extracted, insert screw end of extractor into inlet. Screw end of extractor into fixed orifice tube body. Remove tube body from evaporator core line.

1. Ensure replacement orifice tube is same color as that removed. Lubricate "O" rings on orifice tube with clean refrigeration oil. Place orifice tube into orifice tube remover/installer. Insert orifice tube into evaporator inlet tube until orifice tube bottoms against the stop.
2. Remove orifice tube remover/installer. Install liquid on evaporator using a new "O" ring lubricated with refrigeration oil. Pull backward on liquid line to ensure proper seating of the line. Leak test, evacuate and recharge the system. Check system for proper operation.

1. Orifice tube is located in the line, near the condenser. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. Disconnect liquid line at condenser.
2. To disconnect liquid line, fit appropriate spring lock coupling clamp on the line. See SPRING LOCK COUPLING CLAMP table earlier in article. Close clamp and push into opening side of cage to expand garter spring and release female fitting. After garter spring is expanded, pull coupling apart. (Scheme 11)
3. Using Orifice Tube Remover/Installer (T83L-19990-A), remove orifice tube from the line. If orifice tube breaks in inlet tube, use Broken Orifice Tube Extractor (T83L-19990-B) to remove the orifice tube.

1. Ensure replacement orifice tube is same color as that removed. Lubricate "O" rings on orifice tube with clean refrigeration oil. Using orifice tube remover/installer, install orifice tube.
2. Reconnect line on condenser using a new "O" ring lubricated with refrigeration oil. Leak test, evacuate and recharge the system. Check system for proper operation.

Scheme 14

Scheme 15

1. Orifice tube is located in condenser-to-evaporator liquid refrigerant line near condenser by the 3 indented notches or circular depression in the line. (Scheme 14)
2. Disconnect negative battery cable. Discharge A/C system using approved refrigerant recovery/recycling equipment. To remove liquid line, fit appropriate spring lock coupling clamp on the line. See SPRING LOCK COUPLING CLAMP table earlier in article.
3. Close clamp and push into opening side of cage to expand garter spring and release female fitting. After garter spring is expanded, pull coupling apart. (Scheme 11) Remove liquid line.
4. Locate orifice tube in metal portion of liquid line (3 indented notches or circular depression). (Scheme 14) Note angle positions of liquid line ends for reassembly. Cut a 2 1/2" (63.5 mm) section from tube at orifice location. DO NOT cut closer than 1" (25.4 mm) from start of bend in liquid line. (Scheme 15)
5. Flush out liquid line. Lubricate "O" rings with refrigeration oil. Assemble orifice tube kit on liquid line. (Scheme 15) Ensure replacement orifice tube is the same color as that removed.
6. Ensure flow direction arrow is pointed at evaporator and taper on ferrule is toward the nut. While holding hex of liquid line in a vise, tighten each compression nut to 65-70 ft. lbs. (88-95 N.m).
7. Reconnect line, using a new "O" ring lubricated with refrigeration oil. Leak test, evacuate and recharge the system. Check system for proper operation.

REFRIGERANT RECOVERY

Note. Recent findings by the EPA indicate that refrigerant is harmful to the Earth's protective Ozone layer. When discharging refrigerant, avoid allowing refrigerant to enter the atmosphere. Refrigerant recovery/recycle system should be used.

1. Connect refrigerant recovery/recycle system hoses to high and low side service valves. See SERVICE VALVE LOCATIONS in this article. NOTE: Refrigerant recovery/recycle system hoses should contain shut-off valves or check valves to inimize amount of air that enters the recycle system when hoses are disconnected.
2. Turn refrigerant recovery/recycle system on. Allow unit to run until vacuum is obtained. Once vacuum reading is obtained, close inlet valve on refrigerant recovery/recycle system (if equipped). Shut refrigerant recovery/recycle system off. NOTE: On some applications, the refrigerant recovery/recycle system will shut off because of a low pressure switch in the electrical system on the refrigerant recovery/recycle system. On other applications, the refrigerant recovery/recycle system must be shut off.
3. Allow system to remain closed for approximately 2 hours while observing pressure readings on the refrigerant recovery/recycle system.
4. If pressure reading remains at zero, disconnect hoses from service ports. If pressure reading increases to above zero, repeat steps 2) and 3).

DISCHARGING A/C SYSTEM

Note. Recent findings by the EPA indicate that refrigerant is harmful to the Earth's protective Ozone layer. When discharging refrigerant, avoid allowing refrigerant to enter the atmosphere. Refrigerant recovery/recycle system should be used whenever possible instead of discharging system. Many states now require by law the use of recovery/recycle systems. Check local laws before proceeding.

1. Close both valves on manifold gauge set. Connect manifold gauge set to high and low side service valves. See SERVICE VALVE LOCATIONS in this article.
2. If manifold gauges or charging station are not equipped with depressing pins, install Adapters (T71P-19703-S and R) on high and low pressure hoses.
3. Connect a discharge hose to center connector on manifold gauge set. Place open end of discharge hose in garage exhaust outlet or in a well ventilated area if recovery system is not used. Slightly open low side valve and release refrigerant without losing refrigerant oil.
4. When system is nearly discharged, open high side valve to release any pressure trapped in compressor. Close manifold gauge set valves immediately after discharging to prevent entry of moisture.

FLUSHING A/C SYSTEM .

Manufacturer recommends flushing contaminated system with flushing agent using Rotunda A/C Reclaim System (158-0000 1).

EVACUATING A/C SYSTEM

1. Close both valves on manifold gauge set. Connect manifold gauge set to high and low side service valves. See SERVICE VALVE LOCATIONS in this article. Connect a hose to center connector on manifold gauge set and evacuation pump.
2. Open both valves on manifold gauge set. Start evacuation pump and operate until low side vacuum reading of at least 25 in. Hg is obtained.
3. Continue operating evacuation pump for 15 minutes. If compressor, evaporator, refrigerant line, etc. have been replaced, operate evacuation pump for at least 30 minutes.
4. Close both valves on manifold gauge set. Turn off evacuation pump. Observe low side gauge. If vacuum reading drops in 5 minutes, system has leak. Perform leak testing procedure and repair.

CHARGING A/C SYSTEM

Note. See A/C SYSTEM SPECS in the AIR CONDITIONING section for system capacities. Manufacturer does not recommend using one pound cans. Using a charging station will allow precise measurement of R-12 charge.

1. System must be evacuated before charging. With manifold gauge set attached from evacuation procedures, attach R-12 container to hose on center connector of manifold gauge set. Fully open R-12 container valve and purge air from center hose.
2. Disconnect electrical connector from clutch cycling pressure switch, located on the accumulator. Install jumper wire between connector terminals.connector.
3. Open low side valve on manifold gauge set and allow R-12 to enter system. When no more R-12 is being drawn into system, start and run engine. Place A/C-heater controls on MAX cold position with blower speed on high. NOTE: In high temperature areas, it may be necessary to operate a high volume fan to blow air through condenser and radiator.
4. When proper amount of R-12 has been added, close low side valve on manifold gauge set. Remove jumper wire and connect clutch cycling pressure switch. Reinstall electrical connector.
5. Operate system to verify proper operation and normal system pressures. Disconnect manifold gauges set. Install service port caps. Check system for leaks.

LEAK TESTING

Operate system to stabilize high and low side pressures. Turn engine off. Using an R-12 leak detector, check all refrigerant line connections for leaks. Check compressor seal area and condenser. R-12 is heavier than air. Always check for leaks at bottom of refrigerant lines and components. Refrigerant oil will leak with R-12. Visually check all connections and compressor clutch area for oil stains. If compressor shaft seal is leaking, a fresh oil streak will normally be seen on underside of hood above compressor clutch.

Always perform leak testing after A/C service. Move R-12 leak detector slowly to check for leaks, as leaks will not be detected if leak testing is performed too quickly.