单选题In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）Abroken valve springsBtight drive beltsChigh line voltageDair in the system
单选题
In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）
A
broken valve springs
B
tight drive belts
C
high line voltage
D
air in the system
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