A/C Refrigerant Leak Test

  • Compressed air mixed with R-134a froms 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 system.

  • 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.

Use only service equipment for refrigerant HFC-134a (R-134a).

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.

Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.

1.Connect a R-134a refrigerant recovery/recycling/charging station (A) to the high-pressure service port (B) and the low-pressure service port (C), as shown, following the equipment manufacturer¢s instructions.


2.Open high pressure valve to charge the system to the specified capacity, then close the supply valve, and remove the charging station fittings.

Select the appropriate units of measure for your refrigerant charging station.
Refrigerant capacity: 
400 to 450 g 
0.40 to 0.45 kg 
0.9 to 1.0 lbs 
14.1 to 15.9 oz 

3.Check the system for leaks using a R-134a refrigerant leak detector with an accuracy of 14 g (0.5 oz) per year or better.

4.If you find leaks that require the system to be opened (to repair or replace hoses, fittings, etc.), recover the system.

5.After checking and repairing leaks, the system must be evacuated.