A/C Refrigerant System Tests
A/C REFRIGERANT SYSTEM TESTS
1. Connect the manifold gauge set.
2. Adjust the climate control for maximum cooling.
- Start the engine.
- Select MAX A/C operation.
- Set the blower motor speed to maximum.
3. Stabilize the in-vehicle temperature at 21°C-27°C (70°F-80°F).
NOTE:When the ambient temperatures exceed 38°C (100°F), do not run the engine above normal idle speed.
4. Maintain the engine speed at 1500 rpm.
5. Determine the compressor discharge (high) pressure.
a. Record the ambient temperature.
b. Record the discharge (high) pressure.
NOTE:In ambient temperatures between 38°C-43°C (100°F-110°F), the system performance pressures will be the same as those for ambient temperatures shown on the chart in the 32°C-38°C (90°F-100°F) range.
c. The system performance is acceptable when the pressure reading falls between the upper and lower limits shown below.
6. Determine the compressor suction (low) pressure.
a. Record the ambient temperature.
b. Record the suction (low) pressure.
NOTE:In ambient temperatures between 38°C-43°C (100°F-110°F), the system performance pressures will be the same as those for ambient temperatures shown on the chart in the 32°C-38°C (90°F-100°F) range.
c. The system performance is acceptable when the pressure reading falls between the upper and lower limits shown below.
7. Determine the A/C clutch on time.
a. Record the ambient temperature.
b. Record the A/C clutch on time (for one cycle) in seconds.
NOTE:When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.
c. The system performance is acceptable when the recorded time falls between the upper and lower limits shown below.
8. Determine the A/C clutch off time.
a. Record the ambient temperature.
b. Record the A/C clutch off time (for one cycle) in seconds.
NOTE:When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.
c. The system performance is acceptable when the recorded time falls between the upper and lower limits shown below.
9. Determine the total A/C clutch cycle time.
a. Record the ambient temperature.
b. Record the time the A/C clutch is engaged plus the time it is disengaged (time on plus time off) for one cycle.
NOTE:When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.
c. The system performance is acceptable when the recorded time falls between the upper and lower limits shown below.
10. Determine the A/C clutch cycle rate per minute.
a. Record the ambient temperature.
b. Record the number of A/C clutch cycles occurring in one minute.
NOTE:During A/C operation, the A/C clutch will cycle on (engaged) and off (disengaged). When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.
c. The system performance is acceptable when the recorded number of cycles fall between the upper and lower limits shown.
11. Determine the center A/C register discharge temperature.
a. Record the ambient temperature.
b. Record the center A/C register discharge temperature.
NOTE:In ambient temperatures between 38°C-43°C (100°F-110°F), the A/C register discharge temperatures will be the same as those for ambient temperatures shown on the chart in the 32°C-38°C (90°F-100°F) range.
c. The system performance is acceptable when the center A/C register discharge temperature falls between the upper and lower limits shown.
Refrigerant System Recovery
NOTE:Mazda Motor Company recommends use of an A/C service center to carry out recovery, evacuation and charging of the refrigerant system. If an A/C service center is not available, system recovery, evacuation, and charging may be accomplished using a separate vacuum pump, charging cylinder, and manifold gauge set.
1. Prior to recovering or charging the refrigerant system, you must verify the purity of the refrigerant.
NOTE:Some R-134a service centers require the use of an A/C manifold gauge set.
2. Connect R-134a A/C service center to the low and high pressure service gauge port valves.
3. Recover the refrigerant from the system following the manufacturer's instructions.
4. Once the service center has recovered the vehicle A/C system refrigerant, close the service center inlet valve (if equipped). Then switch off the power supply.
5. Allow the vehicle A/C system to remain closed for about two minutes. Observe the system vacuum level as shown on the gauge. If the pressure does not rise, disconnect the refrigerant center hose(s).
6. If the system vacuum does decrease, repeat steps 2 through 5 until the vacuum level remains stable for two minutes.
7. Carry out the required repairs, then evacuate and recharge the A/C system; see next section.
Refrigerant System Evacuation
NOTE:Mazda Motor Company recommends use of an A/C service center to carry out recovery, evacuation and charging of the refrigerant system. If an A/C service center is not available, system recovery, evacuation, and charging may be accomplished using a separate vacuum pump, charging cylinder, and manifold gauge set.
1. Connect R-134a service center to the low and high pressure service gauge port valves.
2. Evacuate the system until the low pressure gauge reads at least 99.4 kPa (29.5 in-Hg) of vacuum and as close as 101.1 kPa (30 in-Hg) as possible. Continue to operate the vacuum pump for a minimum of 45 minutes.
3. Turn off the evacuation pump. Observe the low pressure gauge for five minutes to make sure that the system vacuum is held. If vacuum is not held for five minutes, leak test the system, service the leaks, and evacuate the system again.
Refrigerant System Charging
NOTE:Mazda Motor Company recommends use of an A/C service center to carry out recovery, evacuation and charging of the refrigerant system. If an A/C service center is not available, system recovery, evacuation, and charging may be accomplished using a separate vacuum pump, charging cylinder, and manifold gauge set.
1. Correctly oil match the system to verify that the correct amount of refrigerant oil is present in the system. See A/C Refrigerant Oil Addition.
2. Charge the system with the specified amounts of refrigerant oil and refrigerant.
3. When no more refrigerant is being drawn into the system, start the engine and select MAX A/C operation. Adjust the blower motor speed to the maximum and allow the remaining refrigerant to be drawn into the system. Continue to add refrigerant into the system until the specified weight of R-134a has been added. Close the charging valve and allow the system to pull any remaining refrigerant from the hose. When the low pressure drops to approximately 297 kPa (43 psi), close the charging hose valve.