In a parallel compressor system, oil often does not return at the same rate to all of the compressors because:

Question

A) Only some of the compressors require oil return.
B) All the compressors do not use the same type of refrigerant oil.
C) All the compressors do not operate for the same length of time.
D) Parallel compressors are normally stacked vertically, so most of the returning oil returns to the crankcase of the bottom compressor.

Answer 1

C