单项选择题
If the compressor runs continually, the cause might be the（）
A.high-pressure cutout switch is jammed open B.low-pressure switch is jammed shut C.thermal bulb is not operating properly D.scale trap is clogged
单项选择题 The bulb for the thermal expansion valve is located（）
单项选择题 The thermal expansion valve responds to the（）
单项选择题 The thermostatic valve has a throttling action, that is to say the valve can（）
