Heating and Air Conditioning: Testing and Inspection

The procedure below should be used to check the refrigerant charge level in the air conditioning system.

WARNING: AVOID BREATHING A/C REFRIGERANT AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY IRRITATE EYES, NOSE AND THROAT. USE ONLY APPROVED SERVICE EQUIPMENT MEETING SAE REQUIREMENTS TO DISCHARGE R-134a SYSTEM. IF ACCIDENTAL SYSTEM DISCHARGE OCCURS, VENTILATE WORK AREA BEFORE RESUMING SERVICE.

R-134a SERVICE EQUIPMENT OR VEHICLE A/C SYSTEM SHOULD NOT BE PRESSURE TESTED OR LEAK TESTED WITH COMPRESSED AIR. MIXTURE OF AIR and R-1 34a CAN BE COMBUSTIBLE AT ELEVATED PRESSURES. THESE MIXTURES ARE POTENTIALLY DANGEROUS AND MAY RESULT IN FIRE OR EXPLOSION CAUSING INJURY OR PROPERTY DAMAGE.

NOTE: Refer to the underhood HVAC specification tag for the proper charge level.

It is recommended to use a manifold gauge set or reclaimirecyde equipment.
1. Use a manifold gauge set and check the liquid line pressure.
2. Attach a clamp-on thermocouple to the liquid line near the evaporator.
3. The vehicle must be in the following modes:
- Automatic transmission in park or manual transmission in neutral.
- Engine at idle
- A/C mode control set to outside air
- A/C mode control set to panel mode
- A/C temperature control set to full cool
- Blower motor control set on highest speed
- Vehicle windows closed
4. Operate the A/C system for at least two mmutes to allow the system to stabilize.

Liquid Line Pressure:

5. Observe liquid line pressure and temperature. Using the Charge Determination Chart determine where the system is currently operating. If the system is not in the proper range, redaim all the refrigerant and recharge per A/C label.