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 A — rising and falling with each stroke

Turning in the discharge service valve isolates the compressor while manual rotation cycles the pistons. If discharge valves leak, high-pressure gas trapped downstream fluctuates back into the cylinder during suction strokes, causing compound gauge pressure to rise and fall.