单项选择题
A.dirt will cause corrosion of bearing B.bearings will leak oil excessively C.dirt is very abrasive when mixed with grease D.grease will become inflammable
The presence of bubbles in a refrigeration system liqui...
单项选择题The presence of bubbles in a refrigeration system liquid line may （）.
A.promote refrigerant dehydration B.be absorbed in the receiver C.cause low condensing pressure D.carry moisture and lead to corrosion
Air entering an air-cooled refrigeration system is indi...
单项选择题Air entering an air-cooled refrigeration system is indicated by （）.
A.frosting of the liquid line B.higher than normal head pressure C.a clear sight glass D.abnormally cold reefer boxes
When installing a hydraulic hose, which of the followin...
单项选择题When installing a hydraulic hose, which of the following precautions should be taken?（）
A.The hose should not be twisted B.The hose should be protected with a sleeve if it is subjected to rubbing C.There should be some slack in the hose D.All of the above
