单选题In a compression refrigeration plant the hot, high pressure refrigerant gas is cooled by the sea water and becomes liquid in the （）.A compressorB condenserC throttle valveD evaporator

If the head pressure of a reciprocating refrigeration compressor is excessive

A.the relief valve should open before the high pressure cutout

B.the relief valve should open and allow the excess refrigerant to flow to the receiver

C.the high pressure cutout switch should operate before the relief valve opens

D.you should close the discharging valve

If fuel injection to a four-stroke/cycle diesel engine begins earlier than designed, ignition may be delayed because the

A.cylinder compression pressure may not be high enough

B.cylinder compression temperature may be too high

C.fuel oil injection pressure may not be high enough

D.scavenge and purge process is incomplete

In the refrigeration system, a shortage of refrigerant is indicated by

A.the compressor short cycling on high pressure cut out switch

B.high suction pressure

C.high head pressure

D.bubbles in the sight glass

If a refrigeration compressor is short cycling on high head pressure, you should

A.purge the condenser if the waterside is dirty

B.check for proper water flow through the condenser

C.increase the high pressure cutout setting

D.reduce the cooling water flow