How should one check the discharge valves on a compressor?

To effectively check the discharge valves on a compressor, front seating the suction service valve and pumping the compressor into a vacuum helps assess whether the discharge valves are operating correctly. This method allows you to observe whether the compressor can maintain a vacuum. If the discharge valves are leaking or not sealing properly, the compressor will struggle to create and hold a vacuum, indicating a potential issue with the discharge valves.

This technique is beneficial because it isolates the compressor from the rest of the refrigerant system, simplifying the evaluation of the valves without the influence of other components. The other methods, such as running the compressor with the discharge open or using a gauge to measure system pressure, do not directly test the sealing capability of the discharge valves. Additionally, disconnecting the discharge line can create safety risks and may not yield effective results for valve assessment.