单项选择题
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
A.a high suction head
B.rotating rings
C.badly worn bearings
D.a loose stuffing box gland
点击查看答案&解析
相关考题
-
单项选择题
A pressure drop through the refrigerant liquid line may cause （）.
A.solenoid valve to seize
B.compressor to hunt
C.formation of flash gas in the liquid line
D.expansion valve to freeze open -
单项选择题
Low compressor head pressure in a refrigeration system can be caused by（）.
A.insufficient condenser cooling water
B.excessive condenser cooling water
C.air in the refrigeration system
D.excessive refrigerant in the system -
单项选择题
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
A.Thermal expansion valve frozen open
B.Suction gas heat exchanger bypassed
C.Condenser clogged or fouled
D.High pressure cutout switch inoperative
