Unit 25 Test and Quiz Review

A

A (n) ______________________ is often placed in or on the suction line leaving the evaporator and improves the evaporator capacity by increasing the liquid subcooling. A. heat exchanger B. evaporator pressure regulator C. refrigerant distributor D. oil separator

A

A ____________ can be used to improve the capacity of the evaporator by subcooling the liquid refrigerant entering it A. heat exchanger B. filter drier C. refrigerant distributor D. check valve

B

A _________________ allows the compressor to cycle on internal overload without affecting the operation of the oil safety control. A. oil pressure transducer B. current sensing relay C. low-pressure switch D. lockout relay

C

A ____________________ has a magnetic coil, can be normally open or normally closed, and is frequently used to control fluid flow (liquid or vapor) A. evaporator pressure regulator B. crankcase pressure regulator C. solenoid valve D. variable frequency drive

C

A __________________________ is used to keep the compressor from operating with high head pressure A. fan-cycling control B. low pressure control C. high-pressure control D. head pressure regulator

A

A component that has a magnetic coil, can be normally open or normally closed, and is used to control fluid flow is a A. solenoid valve B. current sensing relay C. refrigerant check valve D. lockout relay

A

A component used to remove moisture and foreign matter from refrigerant is a (n) A. filter drier B. receiver C. sight glass D. accumulator

D

A control that can be used as either a low-charge protection or to control space temperature is a _____________________ A. low ambient control B. thermostat C. high-pressure switch D. low-pressure switch

D

A type of defrost used by medium-temperature systems that uses the evaporator fans to circulate air in cooler over the coil when the compressor is deenergized is called A. hot gas defrost B. electric heat defrost C. radiant defrost D. off-cycle defrost

C

An automatic pumpdown system may be used to A. maintain a constant evaporator pressure during low load conditions B. raise system head pressure during low-ambient conditions C. prevent surges of liquid refrigerant from entering the compressor (slugging) during start-up D. prevent liquid refrigerant from becoming trapped in the receiver

A

Any evaporator that operates below 32 degrees F _____________________________ A. requires some form of defrost B. must have and EPR and a TXV C. should have a heater in the evaporator to ensure proper oil return D. should have a check valve at its outlet to keep up pressure during the off-cycle

D

Condenser flooding maintains head pressure by A. filling the receiver with liquid refrigerant, raising head pressure B. splitting the condenser into equally sized condensers, referred to as summer and summer/winter C. storing liquid refrigerant in the evaporator during the off-cycle D. backing up liquid refrigerant into the condenser, acting like an overcharge

Terminate defrost when evaporator coil has been defrosted and to delay the evaporator fans from coming on immediately after defrost

Describe the function of a defrost termination/fan delay (DTFD) switch

It separates oil from the refrigerant and the oil goes to the oil reservoir

Describe the function of an oil separator

A

During an automatic pumpdown, the refrigerant is stored in the ______________________ A. condenser and receiver B. receiver C. evaporator and suction line D. evaporator

To hold the refrigerant charge in the outdoor unit while it's being shipped

Explain the function of various refrigeration system service valves

C

Is this an air cooled or a water-cooled ice machine? How can you tell? A. water supply, pump and city connections B. air handled, fan motor and water pump C. water-cooled, the tube in tube coil D. air cooled, the tube and fin coil

False

Net oil pressure is the pressure that can be measured at the discharge or outlet of the oil pump True or False

B

On a "one-time" or non-short-cycling pumpdown system A. a leaking solenoid valve or compressor discharge valve will cause the system to turn back on B. only the thermostat calling again for cooling will take the refrigeration system out of a pumpdown C. the refrigerant is stored in a liquid receiver and must be manually released back into the system D. once the system has been pumped down, it will lock out, requiring service

True

Pressure switches are used to start and stop electrical current flow to refrigeration components True or False

C

Refrigerant relief valves come in two different types, ___________________. A. spring-loaded and electronic B. electronic and mechanical C. spring-loaded and one-time D. mechanical and one-type

A

The ________________ valve can move in very small increments or steps to either open or close the suction line in response to the discharge air temperature of a refrigerated case A. electronic evaporator pressure-regulating B. thermostatic expansion C. electronic expansion D. crankcase pressure-regulating

C

The component located on the outlet of the receiver that can be used to trap the refrigerant into the receiver in order to perform system service is called a (n) A. Schrader valve B. refrigerant distributor C. king valve D. electronic evaporator pressure regulator

D

The component used to prevent compressor oil from having to circulate through the entire system before returning to the compressor crankcase is called a (n) A. oil safety control B. accumulator C. crankcase pressure regulator D. oil separator

B

The component, located on the liquid line, that is used to store liquid refrigerant as it leaves the condenser is called a (n) A. filter drier B. receiver C. refrigerant distributor D. accumulator

D

The component, located on the suction line, that is used to prevent liquid refrigerant from entering the compressor is called a (n) A. filter drier B. reciever C. refrigerant distributor D. accumulator

B

The function of the evaporator pressure regulator is to maintain a A. constant evaporator pressure B. minimum pressure in the evaporator C. constant evaporator temperature D. maximum pressure in the evaporator

D

The purpose of the crankcase pressure-regulating valve is to A. maintain constant pressure in the crankcase B. maintain constant pressure in the evaporator C. prevent a compressor from going into a vacuum D. prevent a compressor overload condition

B

The thermostat is using ____________ to sense internal temperature. A. IR temperature B. product temperature C. air temperature D. water temperature

C

The two forces that control the EPR valve are the _____________________. A. suction line pressure and the evaporator pressure B. valve's spring pressure and the liquid line pressure C. evaporator pressure and the valve's spring pressure D. liquid line pressure and the suction line pressure

C

This reach in cooler uses ___________ to maintain internal temperature. A. natural convection B. radiation C. forced convection D. conduction

C

To prevent the head pressure from dropping to the point that the expansion valve will not feed correctly A. a pumpdown system is used B. an evaporator pressure regulator is used C. low-ambient controls are used D. a high-pressure control is used

B

To throttle or regulate the flow of fluid as opposed to just starting and stopping it is called _____________ A. pulsing B. modulating C. rationing D. mixing

B

Two methods for accomplishing defrost on low-temperature refrigeration systems are A. radiant and electric defrost B. hot gas and electric defrost C. planned and random defrost D. hot gas and off-cycle defrost

C

Two types of off-cycle defrost used on medium-temperature refrigeration systems are A. radiant and electric defrost B. hot gas and electric defrost C. planned and random defrost D. hot gas and off-cycle defrost

A

Two types of relief valves _________________. A. check and spring loaded B. manual and ball C. spring-loaded and one time D. one-time and multiuse

D

What can cause the Hoshizaki ice machine to turn the distribution plates into a giant block of ice? A. Frozen water, scale build up B. Clogged solenoid coil, bad compressor C. Unclean water supply, Stuck float lever D. Residual ice, bad plate connection, and dirty evaporator

A

What can the harvest cycle be compared to in a heat pump? A. Defrost Cycle B. Liquid Receiver C. Reversing Valve D. Accumulator

It will equalize pressure on both side of the liquid column when the compressor is on or off

What is the function of the pressure equalization orifice at the outlet of an accumulator?

A

What kind of ice machine cleaner needs to be used with this ice machine? A. Nickel safe Scale Away B. Soap and water C. Drain Solve D. Bleach

A

What type of metering device does this glass front reach-in cooler use? A. Capillary tube B. TXV C. EEV D. Piston

A

Which of the following is a pressure differential control which protects the compressor from operating without sufficient lubrication? A. Oil safety switch B. Thermostat C. High-pressure switch D. Low-pressure switch

D

Which of the following is not a major component of the compression refrigeration cycle A. Compressor B. Condenser C. Evaporator D. Suction-line drier

A

Which of the following is not a method of low-ambient control on air-cooled equipment? A. Modulating TXV B. Fan-cycling controls C. Condenser flooding D. Fan speed control

D

Which of the following is used as a protection against operation with a low charge or as a temperature control for some refrigeration evaporators? A. Oil safety switch B. Thermostat C. High-pressure switch D. Low-pressure switch

C

Which of the following is used to protect the compressor and high-side system components from operating with excessive pressure? A. Oil safety switch B. Thermostat C. High-pressure switch D. Low-pressure switch

A

Why is it important to maintain the cleanliness of the condenser coil in this glass front reach in cooler? A. Keep the compressor running cool and efficiently B. It prevents allergies C. To improve metering device operation D. Helps keep the product within reach

Prevent nuisance trips of the oil safety controller

Why is there a time delay in an oil safety control?