UTB12 Refrigeration

Question 1

What term is used for the heat absorbed or given off by a substance while it is changing its physical state?

Answer 1

Latent heat

Question 2

Which expansion valve controls the liquid refrigerant flow where a flooded evaporator is used?

Answer 2

Low side float expansion valve

Question 3

Which accessory device consists of a low-pressure bellows or a low-pressure diaphragm connected by a small diagram tube to the compressor?

Answer 3

Compressor-motor control

Question 4

Which refrigerant has become a replacement for R-12 because it is noncorrosive, nonflammable, practically nontoxic, and has a boiling point of -50°F at atmospheric pressure?

Answer 4

R-502

Question 5

In what year was the Montreal Protocol amended to establish a schedule for the phase-out of HCFCs?

Answer 5

1992

Question 6

How often should you weigh a refrigerant cylinder?

Answer 6

Every time refrigerant is discharged

Question 7

(True or False) Goggles are not required when working with refrigerants.

Answer 7

False

Question 8

What type of refrigerator has a manual defrost that requires the unit to be turned off to melt the frost buildup on the evaporator?

Answer 8

Single-door fresh food

Question 9

(True or False) The two basic designs for water coolers, wall mounted and floor mounted, are very different when it comes to construction and operation.

Answer 9

False

Question 10

What type of acid is formed when refrigerant is mixed with water?

Answer 10

Hydrochloric

Question 11

U-traps or oil separators should be installed on multiple compressor systems when the condensers are how many feet above the compressor?

Answer 11

10 feet

Question 12

When transferring refrigerant, the amount of refrigerant that may be placed in a cylinder is what percentage of the tare-weight?

Answer 12

85%

Question 13

What is the best leak detector to use when trying to detect a halogen refrigerant leak?

Answer 13

Halide leak detector

Question 14

What unit valve is considered to be obstructed when the unit runs continuously?

Answer 14

Suction valve

Question 15

What can cause the unit’s compressor to become stuck or tight?

Answer 15

Poor reassembly

Question 16

(True or False). The coupling on the shaft of direct drive motors should be
realigned after any repair or replacement.

Answer 16

True

Question 17

Manually defrosting is normally required on refrigeration units that operate at what temperature?

Answer 17

35°F and lower

Question 18

What does this formula do?

C = (F-32) ÷ 1.8

Answer 18

Formula used to change a Fahrenheit heat reading to a Celsius reading

Question 19

What type of heat changes the temperature of a substance, but not its physical state?

Answer 19

Sensible

Question 20

What is the process called, that changes a vapor into a liquid?

Answer 20

Condensation

Question 21

(True or False) The components of a refrigeration system consist of a compressor, liquid receiver, evaporator, and control devices.

Answer 21

True

Question 22

What type of refrigeration system compressor is bolted together, has a crankshaft that extends through the crankcase, and is driven by a flywheel and belt?

Answer 22

External drive
or
Open type

Question 23

Which expansion valve is used to maintain a constant pressure in direct drive and dry type evaporators?

Answer 23

Automatic expansion valve

Question 24

Which refrigerant is an azeotropic that can only be used with reciprocating compressors?

Answer 24

R-502

Question 25

Which refrigerant has a boiling point of -55.3°F at atmospheric pressure, and is used to replace R-502 refrigerant?

Answer 25

R-125

Question 26

(True or False) When storing refrigerants in a cylinder, it is acceptable to use the same regulator for different types of refrigerants.

Answer 26

False

Question 27

(True or False) Refrigerant cylinders should never be exposed to continuous dampness or salt water.

Answer 27

True

Question 28

Which type of refrigerator has a storage capacity of 15 cubic feet or greater, and is used at Navy installations to store perishable foods in galleys and messes?

Answer 28

Reach-in

Question 29

Which type of refrigerator is the most popular and is frost free?

Answer 29

Two-door refrigerator-freezer

Question 30

(True or False) A common practice is the parallel operation of two or more reciprocating compressors for refrigeration system.

Answer 30

False

Question 31

(True or False) Using two equalizer lines between the crankcase, on above the normal oil level and one below, is a method of piping that maintains proper oil level in two or more compressors.

Answer 31

True

Question 32

What size refrigerant shutoff valve, in inches, should be used when transferring refrigerant from the storage cylinder to the service cylinder?

Answer 32

1/4

Question 33

What is the most sensitive type of leak detector?

Answer 33

Electronic type

Question 34

(True or False) The first step to follow when disassembling a compressor because of knocking is to expose the top of the piston by removing the cylinder head and valve plate.

Answer 34

True

Question 35

(True or False) Fan troubles are very hard to locate and correct during compressor inspections.

Answer 35

False

Question 36

What type of chemical is used in a unit dehydrator to absorb moisture from the refrigerant as it passes through the dehydrator?

Answer 36

Desiccant

Question 37

Which action should be taken to any loose hinge pins that are found on a unit’s door hinge?

Answer 37

Braiding

Question 38

(True or False) Operation and maintenance logs should not be used for spotting troubles in refrigeration equipment.

Answer 38

False

Question 39

(True or False) Maintenance logs can be used to figure future maintenance cost requirements.

Answer 39

True