What is the correct procedure for adding refrigerant to the low side of an AC system?

Adding refrigerant to the low side of an AC system should be done as a vapor in the suction service line because this method ensures that the refrigerant enters the system in a controlled manner. When introducing refrigerant as a vapor, it helps to prevent liquid slugging in the compressor, which can cause damage. The suction line is specifically designed to handle vapor and facilitate its movement into the compressor, allowing for efficient operation and reduced risk of flooding.

In contrast, adding refrigerant as a liquid directly can lead to various problems, such as increasing pressure too rapidly and risking compressor damage. Solid refrigerant is not used in practice since refrigerants are intended to change phase between liquid and vapor for proper functionality. Introducing refrigerant in the condenser coil is not a procedure for the low side; instead, it pertains to the high side of the refrigerant circuit. Therefore, ensuring refrigerant is added in vapor form at the correct point helps maintain system integrity and performance.