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 the discharge service valve inward isolates the compressor while allowing manual rotation. Leaking discharge valves permit high-side pressure to bleed back into the cylinder during the compression stroke, causing the compound gauge needle to fluctuate upward and downward with each manually rotated stroke.