单项选择题
If the high-pressure switch on the compressor opens and stops the compressor a possible cause could be:（）
A.too much cooling water going through the condenser B.not enough refrigerant in the system C.a leak in the evaporator coils D.no enough cooling water going through the condenser
单项选择题 The scale trap is located between the （）
单项选择题 The relief valve is located on the（）
单项选择题 If the compressor-discharge temperature is higher than the receiver temperature（）
