Component Tests and General Diagnostics
REFRIGERANT LEAK TEST
Use only service equipment that is U.L-listed and is certified to meet the requirements of SAE J2210 to remove HFC-134a(R-134a)from the air conditioning system.
CAUTION:
- Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
- Be careful when connecting service equipment
- Do not breathe refrigerant or vapor.
If accidental system discharge occurs, ventilate work area before resuming service.
R-134a service equipment or vehicle air conditioning systems should not be pressure tested or leak tested with compressed air.
WARNING:
- Compressed air mixed with R-134a forms a combustible vapor.
- The vapor can burn or explode causing serious injury.
- Never use compressed air to pressure test r-134a service equipment or vehicle air conditioning systems.
Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
1. Connect a R-134a refrigerant Recovery/Recycling/Charging System to the high-pressure service port and the low-pressure service port as shown in the previous column, following the equipment manufacturer's instructions.
2. Open the high-pressure valve to charge the system to the specified capacity, then close the supply valve, and remove the charging system couplers.
Refrigerant capacity : 22.93 ± 0.88 oz. (650 ± 25g)
3. Check the system for leaks using a R-134a refrigerant leak detector with an accuracy of 14g(0.5 oz)per year or better.
4. If you find leaks that require the system to be opened(to repair or re place hoses, fittings, etc.) recover the system according to the Recovery Procedure.
5. After checking and repairing leaks, the system must be evacuated.
PERFORMANCE TEST
1. Install the manifold gauge set.
2. Run the engine at 2,000 rpm and set the controls for maximum cooling and high blower speed.
3. Keep all windows and doors open.
4. Place a dry-bulb thermometer in the cool air outlet.
5. Place a wet-dry thermometer close to the inlet of the cooling unit.
6. Check that the reading on the high pressure gauge is 1,373-1,575 kPa (14-16 kg/cm2, 199-228 psi). If the reading is too high, pour water on the condenser. If the reading to too low, cover the front of the condenser.
7. Check that the reading on the dry-bulb thermometer at the air inlet at 25-35°C (77-95°F).
8. Calculate the relative humidity from the psychrometric graph by comparing the wet-and dry-bulb reading at the air inlet.
9. Measure the dry-bulb temperature at the cool air outlet, and calculate the difference between the inlet dry-bulb and outlet dry-bulb temperatures.
10. Check that the intersection of the relative humidity and temperature difference falls within the block below. If the intersection is within the block, cooling performance is satisfactory.
PERFORMANCE TEST DIAGNOSIS USING MANIFOLD GAUGE
STANDARD VALUE
If cooling cycle is operating normally, the manifold gauge reading will be approx. 21-28psi (1.5-2.0kg/cm2) for the low pressure side and approx. 206-213psi (14.5-15kg/cm2) for the high pressure side. Inlet temperature should be 30-35°C(80-95°F), with the engine at 2,000 rpm, maximum cooling selected, and the blower on highest level.
DIAGNOSIS
CHECKING FOR REFRIGERANT LEAKS
Always conduct a leak test with an electronic leak detector whenever leakage or refrigerant is suspected and when conducting service operations which are accompanied by disassembly or loosening or connection fittings.
NOTE:
In order to use the leak detector properly, read the manual supplied by the manufacturer.
If a gas leak is detected, proceed as follows:
1. Check the torque on the connection fittings and, if too loose, tighten to the proper torque. Check for gas leakage with a leak detector.
2. If leakage continues even after the fitting has been tightened, discharge the refrigerant from the system, disconnect the fittings, and check their seating faces for damage. Always replace, even if the damage is slight.
3. Check the compressor oil and add oil if required.
4. Charge the system and recheck for gas leaks. If no leaks are found, evacuate and charge the system again.
