A solenoid valve used in a refrigeration system should be installed （）.

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• In setting the valves on a steam-smothering system on a tank vessel，the master control valve to cargo tanks should be（）.

  A . open and individual tank valves open B . open and the individual tank valves closed C . closed and the individual tank valves closed D . closed and the individual tank valves ope

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• In a four-stroke cycle diesel engine the intake valves open （）

  A . before TDC and close after BDC B . after TDC and close after BDC C . before TDC and close before BDC D . after TDC and close before BDC

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• A more sophisticated pressure reducing valve incorporates a pilot valve which controls the fluid above the valve operating piston in response to downstream pressureThe bold and italic word “which” means （）.

  A . a pressure reducing valve B . a pilot valve C . an operating piston D . downstream pressure

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• In setting the valves on a steam-smothering system on a tanker，the master control valve to cargo tanks should be（）.

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• A ruptured diaphragm in a thermostatic expansion valve will cause the valve to （）.

  A . open B . close C . remain in its position D . flood the evaporator with refrigerant

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• If the operating element of a thermostatic valve installed in a diesel engine cooling system malfunctions, it may result in （）

  A . a low level in the engine expansion tank B . excessively high coolant pressure C . improper temperatures D . malfunctioning of the jacket water heater

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• An orifice-check valve placed in a hydraulic system is used to（）

  A . regulate the fluid flow in either direction B . restrict movement of hydraulic fluid in one direction, but allow free movement in the other direction C . allow free movement of hydraulic fluid in both directions D . allow a restricted fluid flow in one direction only

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  A . cam followers B . push rods C . combustion gases D . valve spring

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• If the needle valve in a fuel injection nozzle sticks open （）.

  A . no fuel will be delivered through the nozzle B . the nozzle will overheat and crack C . time of injection will change D . fuel will leak into the drain line

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• A feeler or thermal bulb is used for the expansion valve to （）.

  A . detect the temperature B . detect the pressure C . heat the refrigerant D . accelerate the refrigerant

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• The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.

  A . be jammed B . be opened C . be seated D . be broke

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• Increasing the valve clearance between a valve stem and rocker arm, will result in the valve （）

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• A swing check valve is used in a pipeline to （）.

  A . maintain a preset pressure on the line B . closely regulate the amount of flow C . relieve excessive pressure on the line D . allow flow in one direction only

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• A thermostatic expansion valve is properly controlling evaporator superheatAdjusting this valve to lower the superheat will result in a/an （）.

  A . evaporator pressure decrease B . evaporator coil over-feed C . evaporator capacity increase D . expansion valve diaphragm rupture

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• In （） pumps a closed discharge valve will cause bursting discharge pressure.

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• 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（）.

  A . cause loss of hydraulic oil from the system B . result in extreme damage to the pump C . cause damage to the pump ff not continually drained from the pump casing D . result in the system high side pressure to substantially drop off

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• A cracked diaphragm in a thermostatic expansion valve will cause the valve to （）.

  A . return to a neutral position B . flood the evaporator C . open D . close

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• The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.

  A . assist in a quick cutoff of fuel injection B . allow oil backflow from the injector to the helix C . reduce fuel oil pressure between injection strokes D . meter the quantity of fuel delivered

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• Which of the listed statements is a characteristic of the liquid charged power element used with thermostatic expansion valves?（）

  A . At the designed operating temperature, the liquid refrigerant charge has changed to a vapor B . The liquid refrigerant tends to collect at the bellows or diaphragm and reduces the valve sensitivity C . The sensing bulb is empty of liquid refrigerant charge at the designed operating temperature D . The sensing bulb is never emptied of liquid refrigerant under normal operating conditio

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• A built-up exhaust valve is one in which （）.

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• When a refrigeration compressor is in the ‘off’ cycle, the thermal expansion valve will（）.

  A . always be wide open when the compressor restarts B . continue to operate as if the system were in operation C . remain open until evaporator pressure equalizes, then close until the compressor restarts D . always be completely closed until the compressor restart

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