A reciprocating refrigeration compressor may be tested for leaking discharge valves by stopping the compressor, turning the discharge service valve all the way in, and then turning the compressor over by hand. If the discharge valves are leaking, the compound gage will show pressures which react in which way?

Correct Answer: Option C — rising and falling with each stroke

When testing discharge valves, closing the discharge service valve and manually turning the compressor creates pressure fluctuations if valves leak. The compound gauge will show pressure rising on compression strokes and falling as volume increases.