Checking Procedure
CHECKING PROCEDURETo prevent inaccurate or false readings, make sure there is no refrigerant vapor, shop chemicals, or cigarette smoke in the vicinity of the vehicle. Perform the leak test in calm area (low air/wind movement) so that the leaking refrigerant is not dispersed.
1. Turn engine OFF.
2. Connect a suitable A/C manifold gauge set to the A/C service ports.
3. Check if the A/C refrigerant pressure is at least 345 kPa (3.52 kg/sq.cm, 50 psi) above 16 °C (61 °F). If less than specification, recover/evacuate and recharge the system with the specified amount of refrigerant.
NOTE: At temperatures below 16 °C (61 °F), leaks may not be detected since the system may not reach 345 kPa (3.52 kg/sq.cm, 50 psi).
4. Conduct the leak test from the high side (compressor discharge a to evaporator inlet f) to the low side (evaporator drain hose g to shaft seal l). Perform a leak check for the following areas carefully. Clean the component to be checked and move the leak detected probe completely around the connection/component.
- Compressor
- Check the fitting of high- and low-pressure hoses, relief valve and shaft seal.
- Liquid tank
- Check the refrigerant pressure sensor.
- Service valves
- Check all around the service valves. Make sure service valve caps are secured on the service valves (to prevent leaks).
- After removing A/C manifold gauge set from service valves, wipe any residue from valves to prevent any false readings by leak detector.
- Evaporator
- With the engine OFF, turn the blower fan on High for at least 15 seconds to dissipate any refrigerant traces around the evaporator. Wait a minimum of 10 minutes accumulation time (refer to the manufacturer's recommended procedure for actual wait time) before inserting the leak detector probe into the drain hose.
- Keep the probe inserted for at least 10 seconds. Use caution not to contaminate the probe tip with water or dirt that may be in the drain hose.
5. If a leak detector detects a leak, verify at least once by blowing compressed air into area of suspected leak, then repeat check as outlined above.
6. Do not stop when one leak is found. Continue to check for additional leaks at all system components. If no leaks are found, perform steps 7 - 10.
7. Start engine.
8. Set the heater A/C control as follows;
a. A/C switch: ON
b. Mode: Vent
c. Intake position: Recirculation
d. Temperature: MAX cold
e. Blower fan speed: High
9. Run the engine at 1,500 rpm for at least 2 minutes.
10. Turn the engine off and perform leak check again following steps 4 through 6 above.
Refrigerant leaks should be checked immediately after stopping the engine. Begin with the leak detector at the compressor. The pressure on the high pressure side will gradually drop after refrigerant circulation stops and pressure on the low pressure side will gradually rise, as shown in the graph. Some leaks are more easily detected when the pressure is high.
11. Before connecting the recovery/recycling equipment to the vehicle, check the recovery/recycling equipment gauges. No refrigerant pressure should be displayed. If pressure is displayed, recover the refrigerant from the recovery/recycling equipment lines and then check the refrigerant purity.
12. Confirm the refrigerant purity in supply tank using the refrigerant identifier equipment.
13. Confirm the refrigerant purity in the A/C system using the refrigerant identifier equipment.
14. Discharge the A/C system using approved recovery/recycling equipment. Repair the leaking fitting or component as necessary.
15. Evacuate and recharge the A/C system using approved recovery/recycling equipment and perform the leak test to confirm that there are no refrigerant leaks.
16. Conduct the A/C performance test to ensure that the A/C system works properly.