单项选择题
A.bleeding refrigerant from the condenser
B.opening a drain petcock on the oil separator
C.condensing the water in the heat exchanger
D.using a dehydrator cartridge
单项选择题 A centrifugal pump vibrates excessively during operationUpon disassembling the pump it is found that the impeller is out of balanceWithout an available spare, you should （）.
单项选择题 An axial piston, variable stroke pump is used in a vessels hydraulic steering gearUnder pressure, oil continually leaks out from between the valve plate/cylinder barrel and will（）.
单项选择题 In a flash type evaporator, all saltwater headers are vented through individual vent cocks to the（）.