The relief valve is located on the（）

单项选择题If the compressor-discharge temperature is higher than the receiver temperature（）

A.increase the amount of cooling water to the condenser
B.decrease the amount of cooling water to the condenser
C.add more refrigerant to the system
D.remove some of the refrigerant from the system

单项选择题If the head pressure is too high,（）

A.the relief valve should open before the high-pressure cutout
B.the relief valve should open and let excess refrigerant go to receiver
C.the high-pressure cutout switch should operate before the relief valve opens
D.close in on the suction valve

单项选择题If no gaskets are used in the piping joints of a Freon system, the joints must be（）

A.finished joints
B.welded joints
C.ground joints
D.soldered joints

单项选择题If the temperature in the icebox is too high, the trouble could be（）

A.a clogged scale trap
B.air in the system
C.automatic controls not functioning properly
D.insufficient cooling water to the condenser

单项选择题Air or noncondensable gas is removed from a refrigeration system by a （）

A.separating chamber
B.system of baffles
C.purge valve
D.vacuum reducing valve