A/C - Oil Charge Procedure for R12 and R134a
Group 64Heating and
Air Conditioning
Bulletin Number
64 11 93 (3929)
Woodcliff Lake, NJ
May 1994
Product Engineering
SUBJECT:
Air Conditioning Oil Charge Procedure: R-12/R-134a
MODELS:
All
Situation:
During A/C service/repairs, if too much refrigerant oil is added, the system looses cooling efficiency. Severely oil-overcharged systems may suffer compressor damage. On the other hand, systems with insufficient lubricant may exhibit shortened compressor life.
Correction:
When servicing an A/C system that requires replacement of a major component (e.g. compressor, condenser, evaporator) the following procedure MUST be followed exactly to make certain the proper A/C lubricant level is maintained.
1. All types of A/C systems must be recovered with an approved recycling machine. Follow the machine manufacturer's instructions concerning oil recovery. After the refrigerant is evacuated, drain the recovered used lubricant into an empty measuring bottle.
2. Remove the necessary A/C components according to the appropriate repair manual instructions.
3. Drain as much as possible of the oil remaining in every removed component into the same measuring bottle used in Step (1). Accumulate all of the drained/extracted oil into this same bottle.
Note:
When draining a compressor, it may be helpful to turn the clutch plate by hand to "pump" out any remaining oil.
4. Measure and write down the total extracted/drained amount in the measuring bottle.
5. If the compressor is being replaced, the entire oil content of the new compressor (compressors are shipped containing oil) must be drained into a clean, dry container. Turn the clutch plate by hand, as in Step (3), to remove as much oil as possible.
6. Reassemble all components of the A/C system.
7. Fill the recharging machine oil injection bottle with fresh oil. The amount poured into the bottle must be equal to the total amount written down from Step (4). Make certain the injection bottle is clean, and use the fresh oil removed from the new compressor, or a new can of refrigerant oil if the compressor is not being replaced.
8. Apply a deep vacuum for a minimum of 30 minutes to remove any moisture that has entered the system. A vacuum decay test should be used at this time to check for any leaks. Using the charging machine manufacturer's instructions, inject into the A/C system the fresh oil from the bottle filled in Step (7).
9. Dispose of all remaining fresh/used oil properly - do not attempt to store or reuse refrigerant oils.