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A medium-temperature refrigeration box typically operates within what temperature range? a. 40°F to 60°F b. 28°F to 40°F c. 0°F to 50°F d. 0°F to 220°F

28°F to 40°F

A refrigeration system's evaporator typically runs at about ________ of superheat. a. 15°F to 20°F b. 8°F to 12°F c. 12°F to 15°F d. 3°F to 8°F

8°F to 12°F

An evaporator that does not operate flooded is thought of as what type of evaporator? a. A dry-type evaporator b. A low-pressure evaporator c. A float-type evaporator d. A starved evaporator

A dry-type evaporator

What does a high evaporator superheat indicate? a. Low evaporator heat load b. A flooded evaporator c. A starved evaporator d. Proper system operation

A starved evaporator

Natural-convection evaporators use a blower to force or induce air over the coil to improve the efficiency of the heat exchange. a. True b. False

False

What is commonly used to defrost the ice from a low-temperature evaporator? a. Off-cycle or manual defrost. b. Hot gas or electric resistance heat defrost. c. Low-temperature evaporators do not require a defrost. d. Random or off-cycle defrost.

Hot gas or electric resistance heat defrost.

What is the function of the evaporator in the refrigeration system? a. To add humidity to the space being refrigerated. b. It absorbs heat into the refrigeration system. c. It condenses superheated refrigerant vapor to a liquid. d. To add heat to the space or product being cooled

It absorbs heat into the refrigeration system.

Which of the following is not a function of an evaporator efficiency control? a. Initiates a defrost when coil efficiency drops below 90%. b. Regulates condensate removal by activating a condensate pump. c. Contains an Ethernet network device that supports industry standard protocols. d. Monitors evaporator efficiency and performance.

Regulates condensate removal by activating a condensate pump.

What determines the pressure on the low-pressure side of the system? a. The condensing temperature of the refrigerant in the condenser. b. The length of the liquid line feeding the TXV. c. The boiling temperature of the refrigerant in the evaporator. d. The relative humidity percentage in the conditioned space.

The boiling temperature of the refrigerant in the evaporator.

Why is a multicircuit evaporator used? a. To ensure proper compressor operation. b. To prevent ice buildup on the fins. c. They are easily defrosted in low-temperature applications. d. To reduce pressure drop through larger evaporators.

To reduce pressure drop through larger evaporators.

When moisture is removed from the air, latent heat is removed. a. True b. False

True

When liquid refrigerant floods the compressor crankcase, the oil level in the crankcase can drop causing _______. a. condenser flooding b. bearing washout c. valve damage d. excessive superheat

bearing washout

Refrigerant in the evaporator ___________. a. changes from vapor to liquid b. changes from liquid to vapor c. stays in the liquid state d. stays in the vapor state

changes from liquid to vapor

The difference in temperature between the boiling refrigerant temperature and the evaporator outlet temperature is known as ___________. a. suction line superheat b. delta T c. temperature difference d. evaporator superheat

evaporator superheat

Flooded evaporators typically use a(n) ________ type of expansion device. a. float b. automatic c. fixed-bore d. TXV

float

When a refrigerated space has been allowed to warm up considerably, the system must ________. a. go through a hot pulldown b. be defrosted at regular intervals c. turned off and the product being cooled moved to another cooler d. be overcharged to remove the excess heat

go through a hot pulldown

Low-temperature evaporator coils __________. a. have fewer fins per inch than medium temperature evaporator coils b. operate the same as medium temperature evaporator coils c. require more oil circulation that medium temperature evaporator coils d. have more fins per inch than medium temperature evaporator coils

have fewer fins per inch than medium temperature evaporator coils

Two common methods for defrosting a low temperature evaporator are __________. a. hot gas and electric heat b. off-cycle and electric heat c. off-cycle and hot gas d. reverse cycle and hot gas

hot gas and electric heat

Check My Work When an evaporator experiences a heat-load increase, the suction pressure ___________. a. remains constant b. varies up and down c. decreases d. increases

increases

A finned-tube evaporator equipped with fans is called a(n) ________ evaporator. a. liquid-cooling b. induced- or forced-draft c. stamped d. bare-tube

induced- or forced-draft

Flooding the compressor crankcase with liquid refrigerant can cause ________. a. oil foaming b. a starved evaporator c. excessive superheat d. moisture to accumulate in the compressor oil

oil foaming

A low evaporator superheat may indicate a(n) ____________. a. system restriction b. undercharge c. overcharge d. high heat load

overcharge

A medium-temperature evaporator uses a(n)_________ defrost method. a. electric resistance heat b. hot gas c. random or off-cycle d. liquid-injection

random or off-cycle

When the evaporator removes heat from the air and lowers the temperature of the air, _________. a. moisture is added to the air b. refrigerant vapor condenses to liquid c. sensible heat is removed from the air d. latent heat is added to the air

sensible heat is removed from the air

The sensible heat that is added to a saturated vapor after all of the liquid has boiled away is referred to as ________. a. superheat b. subcooling c. latent heat d. specific heat

superheat

The greater the difference in temperature between the evaporator and the air being cooled, ______________. a. the more moisture will be added to the air b. the more moisture will be removed from the air c. the less moisture will be added to the air d. the less moisture will be removed from the air

the more moisture will be removed from the air

The difference in the amount of heat (in Btu/lb) that the refrigerant contains at the point where it enters the evaporator and the point at which it leaves the evaporator is known as _________. a. mass flow rate b. the net refrigeration effect c. the heat of compression d. total heat of rejection

the net refrigeration effect

The best heat exchange occurs between ___________. a. a vapor and a liquid b. two liquids c. a liquid and a solid d. two solids

two liquids

Low-temperature refrigeration systems typically operate at what temperature range? a. −50°F to −20°F b. 0°F to 35°F c. −20°F to 0°F d. 28°F to 40°F

−20°F to 0°F