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

<dd id="99opj"></dd>

單項選擇題

Before charging a refrigeration unit, the refrigerant charging lines should be（）

A.flushed with clean refrigerant oil
B.purged with the refrigerant
C.washed with an ammonia and alcohol solution
D.grounded to compressor

你可能感興趣的試題

單項選擇題

In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decomposes and from （）.

A.petroleum crystals
B.phosgene gas
C.water vapor
D.carbon monoxide

單項選擇題

In an operating refrigeration system low on refrigerant, a liquid line sight glass will（）

A.be clear
B.be blue
C.be light green
D.show bubbles