97免费在线观看视频,亚洲综合自拍网,黄色毛片免费观看,热久久综合网,免费看日产一区二区三区狠狠操av,久久久涩涩涩,在线精品免费视频,人人插天天干,久久91精品国产91久久

<source id="kows5"></source>

<ruby id="kows5"><xmp id="kows5"></xmp></ruby>

單項選擇題

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

你可能感興趣的試題

單項選擇題

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

單項選擇題

The usual symptoms of cavitation in a centrifugal pump is （）.

A.noise and vibration
B.an increase in discharge pressure
C.an increase in suction pressure
D.lifting of the relief valve

<ins id="anqlc"></ins><ruby id="anqlc"><output id="anqlc"></output></ruby>

<dd id="anqlc"></dd>