Adding Refrigerant

Adding Refrigerant

CAUTION: If oil was drawn out during the recovery process, the correct amount may be added directly from the recovery, recycle and recharge station (if so equipped) prior to the charging process. It must be stressed that the need to protect compressor oil from moisture is vital, observe the procedures in HANDLING LUBRICATING OIL and those concerning excessive engine speed.


In order that the air conditioning system may operate efficiently it must contain a full refrigerant charge. The indications of some system defects, and the results of certain tests, will show that a low charge is the most probable cause of the fault. In such cases the charge should be recovered from the system, the weight noted, and the correct amount added.

Should refrigerant be added in liquid form, the engine speed must not exceed 2000 rpm for a period of two minutes after first running the compressor. If the engine speed is excessive, compressor damage may occur due to the lubricating oil and the liquid refrigerant being initially forced around the system as a 'slug', thus taking oil away from the compressor. These marginal lubrication conditions in the compressor will cease as the refrigerant becomes gaseous.

Never attempt to estimate the amount of refrigerant in a system. Always recover and recharge with the correct charge weight; this is the only accurate method.