When recovering contaminated refrigerant, the high-side gauge should be connected to which line?

• A. The liquid line
• B. The suction line
• C. The discharge line
• D. The service port

Answer: (A)

High-side pressure is measured on the high-pressure side of the system, which is the liquid line after the condenser. Connecting the high-side gauge to the liquid line service port gives an accurate reading of the high-pressure condition as refrigerant is recovered, and provides a proper path for the refrigerant to flow into the recovery equipment. The suction line is the low-pressure side, so it belongs with the low-side gauge, and the discharge line (compressor outlet) isn’t the standard service connection for gauges. The service port on the liquid line is specifically where you attach the high-side connection, making the liquid line the correct choice.