Modern refrigeration and air conditioning Ch. 17-20

Question 1

What happens to the high and low side pressures during the off cycle?

Answer 1

They become equal.

Question 2

Fast freezing preserves food better than slow freezing because…

Answer 2

Slower oxidation and foods form smaller water crystals (less damaging).

Question 3

Refrigerator should be set to maintain product temperature of _____ or less

Answer 3

40°F (4.5°C)

Question 4

What is the main advantage of a chest freezer compared to an upright freezer?

Answer 4

Efficiency! less cold air lost when lid is opened (cold air falls)

Question 5

The evaporator in most refrigerator-freezers is located…

Answer 5

In the freezer compartment top of cabinet

Question 6

In a refrigerator-freezer, the percentage of cold air that is delivered to the fresh-food compartment is controlled by the ______

Answer 6

Damper

Question 7

The outer shell of a refrigerator-freezer is typically made from….

Answer 7

Sheets of steel

Question 8

When closed, the refrigerator door seals tightly to the cabinet because of ________

Answer 8

small magnets in the gasket

Question 9

Wine cooler doors are typically made of _____

Answer 9

Double-paned, tempered, safety glass

Question 10

Is it common for a domestic refrigerator-freezer to contain some liquid refrigerant in the evaporator?

Answer 10

Yes.

Question 11

What is the common evaporator temperature range in a domestic refrigerator-freezer?

Answer 11

0°F to -25°F (-18°C to -32°C)

Question 12

most common compressor used in domestic refrigerators?

Answer 12

Split Phase

Question 13

on start up a motor may draw an overload of up to __%

Answer 13

600%

Question 14

poor air circulation in a natural draft condenser =

Answer 14

high head pressure, incresed run-time, and insufficient cooling.

Question 15

hot wall condenser uses

Answer 15

tubing that is in direct contact with the outer wall of the cabinet which serves as a heat sink

Question 16

forced draft condenser does…

Answer 16

takes air in from the front of the refrigerator and expells the air out of the back

Question 17

cardboard partitions do what?

Answer 17

direct air flow

Question 18

most common metering device in domestic refrigerators

Answer 18

capillary tube

Question 19

what is the purpose of the filter drier

Answer 19

to prevent moisture from entering the metering device where it could freeze and cause clogging

Question 20

what does the evaporator do

Answer 20

absorbs heat in the cabinet when refrigerant passes through it

Question 21

what is the purpose of the heat exchanger between the capillary tube and suction line

Answer 21

to prevent liquid refrigerant to the compressor and to provide sub cooling to liquid refrigerant before it enters the evaporator

Question 22

most common fixed temperature range in domestic refrigerators

Answer 22

37-41°f

Question 23

semi automatic defrost

Answer 23

button must be pressed to begin defrost cycle and it automatically cycles back to normal run

Question 24

automatic defrost

Answer 24

electric heating element next to evaporator with a timer operates during the off cycle

Question 25

demand defrost

Answer 25

active based on number of times refrigerator is opened

Question 26

continuous defrost

Answer 26

counts down to next defrost cycle no matter if compressor is running

Question 27

timed defrost

Answer 27

uses a timer to set a predetermined time to defrost

Question 28

mullion heater

Answer 28

electric heater installed arounf the door openings to prevent condensation from forming

Question 29

flow of wate in automatic ice makers are regualted by

Answer 29

solenoid water valve

Question 30

low water pressure can make ____ ice cubes

Answer 30

hollow

Question 31

3 steps to automatic ice maker

Answer 31

fill, freeze, harvest

Question 32

best method of cutting capillary tubing is...

Answer 32

making a notch with a file and bending the tubing back and forth

Question 33

2 methods for crushed ice

Answer 33

auger and reverse auger

Question 34

refrigerators should only be installed in rooms that are __ square ft or larger

Answer 34

100

Question 35

there should be serveral large loops in refrigerator water line to?

Answer 35

move the refrigerator with out disconnecting the water connection

Question 36

an extention cord may cause ?

Answer 36

an un exceptable voltage drop

Question 37

hot wall condenser refrigerator must have atleast \_\_" of air space

Answer 37

2

Question 38

if a refrigerator does not start and the inside light does not come on what is most likely the problem

Answer 38

elecrical circuit

Question 39

a leaky door gasket can cause ...

Answer 39

build up of frost on the evaporator

Question 40

what can prevent a newly installed ice maker from working properly

Answer 40

if the lice maker temp is held at 20 °f

Question 41

compressor condition, storage space, and temperature outside of the cabinet affects what

Answer 41

freezer cycling time

Question 42

over charge of refrigerant can result in

Answer 42

frost on the suctionline

Question 43

a system has symptoms of restriction in the metering device but begins acting normally when heat is applied what is the most likely cause

Answer 43

moisture in the system

Question 44

condenser and compressor should be cleaned atleast...

Answer 44

every three months

Question 45

a vacuum with a brush attachment can be used to ...

Answer 45

clean the compressor and condensor

Question 46

in a compressor burn out ___ mixes with refrigerant and oil cause an odor

Answer 46

burnt electrical wiring

Question 47

a filter drier on the high side should be installed at the

Answer 47

capillary tube inlet

Question 48

a second filter drier on the low side will prevent what

Answer 48

repeat compressor burnout

Question 49

indication a system is low on refrigerant

Answer 49

high low side pressure

Question 50

oil should be replaced when?

Answer 50

in the event of a leak

Question 51

when discarding a refrigerator you must

Answer 51

remove the doors, reclaim the refigerant, and place a label indicating the refrigerant has been reclaimed