单项选择题
For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?（）
A.Chilled water system supply temperature B.Chilled water system return temperature C.Compressor discharge temperature D.Compressor suction pressure
单项选择题 The flame safeguard control system of a large automatic auxiliary boiler will provide fuel shut off in the case of high （）.
单项选择题 The operating water is supplied under the （）of an oil separator.
单项选择题 The （）has a water damp ring.
