更多"If the head pressure is too high,（）"的相关试题:
[单项选择]The pressure head of a water pump is given in the unit of （）.
A. kg
B. MPa
C. mH20
D. None of the above
[单项选择]The pressure head of a pump is given in the unit of （）.
A. kg
B. MPa
C. meter fluid column
D. None of the above is true
[单项选择]One cause of high head pressure occurring in a refrigeration system can be （）.
A. insufficient cooling water flow to the condenser
B. a low refrigerant charge in the system
C. the liquid valve is open too much
D. high evaporator superheat
[单项选择]High pressure and low pressure alarms must be tested（）.
A. no earlier than 24 hours prior to loading
B. no later than 24 hours prior to loading
C. anytime prior to loading
D. weekly
[单项选择]Low cylinder compression pressure and a high exhaust temperature may indicate （）
A. early fuel injection timing
B. leaking valves
C. a continuously open scavenge air port
D. low cooling water temperature
[单项选择]Low compressor head pressure in a refrigeration system can be caused by（）.
A. insufficient condenser cooling water
B. excessive condenser cooling water
C. air in the refrigeration system
D. excessive refrigerant in the system
[单项选择]If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
A. the relief valve should open before the high pressure cutout
B. the relief valve should open and allow the excess refrigerant to flow to the receiver
C. the high pressure cutout switch should operate before the relief valve opens
D. you should close in on the suction valve
[单项选择]An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
A. restriction in refrigerant piping
B. air and non-condensable gases in the condenser
C. water in the refrigerant
D. flooding back of liquid refrigerant from the evaporator
[单项选择]The device used for low-pressure control and high-pressure cutout on a compressor is called a（）
A. cutout
B. pressure controller
C. controller switch
D. cutout switch
[单项选择]The greater the pressure difference between a high and a low pressure center，the（）.
A. dryer the air mass will be
B. cooler the temperature will be
C. greater the force of the wind will be
D. warmer the temperature will be
[单项选择]In order to withstand fluid head pressure on a ship，stiffeners are often attached to the bulkhead（）.
A. penetrations
B. plating
C. framing
D. brackets
[单项选择]In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）
A. broken valve springs
B. tight drive belts
C. high line voltage
D. air in the system
[单项选择]（） provides the head or pressure to supply the domestic water where required.
A. The compressed air
B. The compressing air
C. The transfer pump
D. The head tank
[单项选择]High cylinder firing pressure, accompanied by low exhaust temperature, can result from （）
A. improper fuel rack positing
B. lengthy exhaust valve duration
C. extend operation at light load
D. excessively early injection timing
[单项选择]Which will cause the high pressure cutout to stop the compressor in a R-22 system?（）
A. Condenser leakage
B. A shortage of liquid refrigerant
C. Excessive frost on the evaporator
D. Not enough condenser cooling water
[单项选择]The steam coils in a high pressure evaporator used for saltwater service should be de-scaled with （）.
A. a needle gun
B. soap and water
C. a wire brush
D. a chipping hammer
[单项选择]What separate the high pressure side from the low pressure side in a refrigeration system?（）
A. Condenser and thermal expansion valve
B. King and solenoid valves
C. Compressor and thermal expansion valve
D. Condenser and solenoid valve
[单项选择]As a high pressure system approaches，the barometer reading（）.
A. stays the same
B. falls
C. rises
D. falls rapidly
