Manual A/c-Heater Systems - HVAC: Overview Mazda Tribute I

REFRIGERANT IDENTIFICATION TESTING

Note. Prior to recovering or charging the refrigerant system, you must use an A/C refrigerant analyzer to identify gas samples taken directly from the refrigeration system or storage containers.

1. Follow the instructions included with the refrigerant analyzer to obtain the sample for testing.
2. The analyzer will display one of the following: A green "PASS" light emitting diode (LED) will light if the purity of the R-134, R-12 or the R-22 is better than 98% by weight. A red "FAIL" LED will light if the purity of the gases does not meet the 98% purity standard. A red "FAIL" LED and "HYDROCARBON" light will illuminate and a horn will sound if a hydrocarbon is detected above 5%. This will alert the user of potential hazards.
3. If contaminated refrigerant is detected, DO NOT recover the refrigerant into your recovery/recycling equipment. For additional information, refer to «CONTAMINATED REFRIGERANT HANDLING»(ref-139434-S01884112092005050900000) .

Principles of Operation

There are four main principles involved with the basic theory of operation

1. heat transfer
2. latent heat of vaporization
3. relative humidity
4. effects of pressure

Climate Control Operation

The climate control system is a manual system which heats or cools the vehicle depending on the function selector switch position and the temperature selected.

1. The function selector switch is a vacuum and electrical switch that controls the A/C compressor and air distribution.

Scheme 8

1. The temperature control switch is a cable operated system that controls the air temperature door.
2. The heater blower motor switch varies the blower motor speed.

Scheme 9

When MAX A/C is selected

1. The air inlet blend door is at full vacuum, closing off outside air and allowing only recirculated air.
2. The defrost blend door is at full vacuum while the footwell blend door is at no vacuum, closing both doors.
3. The vent/register blend door is at partial vacuum, directing airflow to the driver-side, passenger-side and center registers.
4. Temperature control is usually set for maximum cold but may be heated if selected.
5. Air is picked up at the recirculation opening by the blower motor. With the temperature control set for maximum cold, air flows across the A/C evaporator core, diverting past the heater core and then directed into the passenger compartment through the driver-side, passenger-side and center registers.
6. The A/C compressor is enabled when MAX A/C is selected.
7. The blower motor is on.

Scheme 10

When A/C is selected

1. The air inlet blend door is set at no vacuum, blocking the recirculation passage and admitting outside air.
2. All other door positions are the same as described under MAX A/C.
3. Temperature setting can be changed manually.
4. The A/C compressor is enabled when A/C is selected.
5. The blower motor is on.

Scheme 11

When panel is selected

1. The air inlet blend door, with no vacuum being applied, blocks recirculated air and allows outside air. Air flows through the system to the driver, passenger and center registers.
2. The vent/register blend door is at partial vacuum to direct airflow to the driver, passenger and center registers.
3. The defrost blend is at full vacuum and defrost airflow door is at no vacuum, closing off airflow to the windshield defroster hose nozzles and footwell ducts.
4. The temperature setting can be changed manually to heat the air but air cannot be cooled below the outside temperature.
5. The A/C compressor is disabled when VENT is selected.
6. The blower motor is on.

Scheme 12

When OFF is selected

1. The air inlet blend door is at full vacuum, closing off outside air and allowing only recirculated air.
2. The vent/register blend door is at no vacuum and the defrost, footwell and blend airflow doors are at no vacuum, closing off the passages to the driver, passenger and center registers.
3. The blower motor and the A/C compressor are off.

Scheme 13

When PANEL/FLOOR is selected

1. The air inlet blend door is set at no vacuum, blocking the recirculation passage and allowing outside air.
2. The footwell blend door is in the full vacuum position, and the panel airflow door is in the full vacuum position allowing airflow to blend between the panel vents and the footwell ducts.
3. The defrost airflow door is at full vacuum, closing off airflow to the windshield defroster hose nozzle and directing airflow to the heater outlet footwell duct.
4. The blower motor is on.

Scheme 14

When FLOOR is selected

1. The air inlet blend door is in the no vacuum position, blocking recirculation air and allowing outside air.
2. The footwell airflow door is at the full vacuum position, opening the door and allowing airflow through the footwell ducts.
3. The defrost airflow door and the vent/register blend door are in the no vacuum position, closing off airflow to the windshield defroster hose nozzles and driver, passenger and center registers.
4. The temperature control can be positioned to mix air flowing through and around the heater core to achieve the selected temperature level.
5. The A/C compressor is disabled when FLOOR is selected.
6. The blower motor is on.

Scheme 15

When FLOOR/DEFROST is selected

1. The air inlet blend door is in the no vacuum position blocking recirculation air and allowing outside air.
2. The footwell blend door is at full vacuum allowing air to flow through the footwell ducts.
3. The defrost blend door is in the no vacuum position, allowing airflow to both the windshield defroster hose nozzle and side window demister hose nozzle ducts.
4. The vent/register blend door is in the no vacuum position.

1. The A/C compressor is enabled when FLOOR/DEFROST is selected to dehumidify the air and reduce windshield fogging.
2. The blower motor is on.

Scheme 16

Scheme 17

When DEFROST is selected

1. The air inlet blend door is in the no vacuum position, allowing outside air.
2. The defrost blend door is at no vacuum, directing the airflow to the windshield through the defroster ducts and the side windows through the demister ducts.
3. The panel airflow door and the footwell airflow door are in the no vacuum position so that most of the incoming air is directed to the windshield defroster hose nozzle. There is also airflow to the side window demister and hose.
4. The temperature control knob setting will determine the amount of air that is directed through the heater core and the amount that bypasses the heater core.
5. The A/C compressor is enabled when DEFROST is selected to dehumidify the air and reduce windshield fogging.
6. The blower motor is on.

Scheme 18