Adding Refrigerant Oil

It is imperative that the specified type and quantity of refrigerant oil be maintained in a refrigerant system for proper operation. A surplus of oil, the wrong oil viscosity or insufficient oil will all cause refrigerant system problems. Insufficient oil or the wrong oil results in poor lubrication and possible compressor damage. A surplus of oil allows too much oil to circulate with the refrigerant causing the cooling capacity of the system to be reduced.

When it is necessary to replace a component of the refrigeration system, certain procedures must be followed to ensure that the total oil charge in the system is correct after the new part is installed. During normal A/C operation, some refrigeration oil is circulated through the system with the refrigerant and some is retained in the compressor. If certain components of the system are removed for replacement, some of the refrigerant oil will go with the component. To maintain the original total oil charge, it is necessary to compensate for the oil loss by adding oil to the system with the replacement part. The procedures for replacing lost oil follow.

Compressor

Refer to Section 12-03B (10P15C) or 12-03C (6P148) for compressor refrigerant oil information and replacement.

Accumulator/Drier

NOTE: If more than 147.85ml (5 oz) of refrigerant oil is removed from an accumulator/drier, it is an indication that the oil drain hole in the accumulator/drier is plugged. Always check the accumulator/drier for excessive oil if the compressor has been replaced for lack of performance.

After removing the accumulator/drier, drain the oil through the Schrader valve fitting of the pressure switch with the valve stem removed. Collect the oil in a calibrated measuring container. Add the same amount of clean refrigerant oil to the new accumulator/drier after it has been installed.

Evaporator Core

Add 88.7ml (3 oz) of clean refrigerant oil to the accumulator/drier inlet tube whenever the evaporator core is replaced. This will compensate for the refrigerant oil lost in the replaced evaporator core.

Condenser

Add 29.5ml (1 oz) of clean refrigerant oil to the condenser or the accumulator/drier if the condenser is replaced.