In what way can liquid refrigerant be charged into the system?

Charging liquid refrigerant into the system typically should be done on the low side through the evaporator service valve. This method allows for proper absorption of the refrigerant within the evaporator coil, ensuring efficient cooling operation and preventing damage to the compressor.

When liquid refrigerant is introduced into the high side through the discharge service valve, this can lead to several problems. The high side is designed to handle gas refrigerant that has already been compressed, and injecting liquid refrigerant at this point can cause liquid slugging in the compressor. Liquid slugging occurs when liquid refrigerant enters the compressor during the compression cycle, which can result in catastrophic failure or damage to the compressor, as it is not equipped to handle liquid in the compression chamber.

Thus, the preferred and safest method for charging liquid refrigerant into an AC or refrigeration system is to do so through the low side service valve, allowing the refrigerant to vaporize and absorb heat as it travels through the evaporator.