Refrigeration

Front 1

Why must air be eliminated from any system by the use of a vacuum pump prior to refrigerant being added?

Back 1

Water in air will damage the compressor.

Front 2

One ton of cooling is the amount of BTU’s needed to freeze 1 tone of water (32F) into 1 ton of ice.

One ton of cooling =

Back 2

12000BTU per hour

288000 BTU’s per day

200 btu per minute

Front 3

What does a compressor do?

Back 3

Compresses cool vapour I to superheated vapour

Front 4

Where is the condenser coil located?

Back 4

Outdoors

Front 5

Superheated vapour enters the condenser coil where a fan blows ambient air or water across the coil to reduce the temperature of the refrigerant.

This cooling will cause the refrigerant to _______

Back 5

Liquefy

Front 6

Where is an evaporator coil located ?

Back 6

In the plenum

Front 7

An evaporator coil allows the liquid from the condenser coil to flash into ______ due to a lowering of ______.

Back 7

Vapour

Pressure

Front 8

As the refrigerant vapourizes it absorbs ______ from the evaporator coil.

The cool coil surfaces remove the ______ from the circulating air and also remove some humidity.

Back 8

Heat

Heat

Front 9

The Humidity removed from the circulating room air drains into a drip pan where it’s directed to a drain pipe that is trapped to prevent __________.

Back 9

Air flow through the drain.

Front 10

High velocity air flow can cause _______________from the drip pan into the supply air duct.

Back 10

Moisture carry over.

Front 11

Evaporator coils may freeze up due to the water condensing on it. To help prevent freeze up, the evaporator should be installed ________than the condenser or a _____valve should be installed.

Back 11

A little larger

TX Valve

Front 12

To better control the temperature of the evaporator, a thermostatic expansion (TX) valve should be installed on the _______ of the evaporator.

Back 12

Inlet

Front 13

What should be installed on the outlet of the evaporator?

Back 13

Temperature sensor

Front 14

What happens when the evaporator coil gets cold enough to freeze water?

Back 14

The TX valve will close a little, regulating the temp of the evaporator coil.

Front 15

The TX valve consists of a ___________________ connected to a ________.

Back 15

Liquid bulb with a capillary tube

Bellows

Front 16

The Bellows is connected to a ____________________.

Back 16

Valve that is spring loaded in the closed position.

Front 17

What are the pressures that cause a TX to react?

Back 17

Spring pressure

Bulb pressure

Liquid pressure

Front 18

What would happen if the Bulb lost its charge?

Back 18

The TX would never open as the spring would close it.

Front 19

Refrigerant vapour pressure and spring pressure act to _____the TX valve.

Back 19

Close

Front 20

Bulb Pressure and Liquid refrigerant pressure act to _____the TX valve.

Back 20

Open

Front 21

3 sections of a heat/cool rooftop unit

Back 21

Heating

Cooling

ventilation

Front 22

An economize is a damper that provides _______ if the outdoor air temperature is cool enough.

Back 22

Free cooling

Front 23

What does a crankcase pressure regulator do?

Back 23

Prevents the compressor from exceeding the full load amperage .

Front 24

An oil failure safety uses ______and ______ _____to operate.

Back 24

Suction

Oil pressure

Front 25

What is the function of the condenser coil?

Back 25

To eject the heat from superheated Vapor causing it to condense into liquid

Front 26

What terminals would activate the cooling cycle?

Back 26

R-Y

Front 27

What do rooftops units use a thermistor for?

Back 27

To monitor the ambient temperature in a room and provides a changing signal to the controller

Front 28

What terminals activate heating cycle?

Back 28

R -W

Front 29

What terminals control the cooling?

Back 29

R-Y

Front 30

How many pressure changes and heat transfers in an air conditioning cycle?

Back 30

2 of each

Front 31

What is the function of the compressor?

Back 31

To compress Vapor refrigerant into superheated vapour

Front 32

What is the function of a liquid metering device?

Back 32

Controls the amount of refrigerant into the evaporator

Front 33

What is the purpose of the Y1 and Y2 terminals as well as W1 and W2 terminals?

Back 33

To allow for 2 stage heating and cooling

Front 34

What is saturation pressure?

Back 34

The pressure at any given time at which liquid and vapour can exist in an equilibrium

Front 35

Liquid cannot become a gas unless it absorbs heat which does not raid it’s temperature. This is know as latent heat of _________

Back 35

Vaporization

Front 36

Liquid cannot become a gas unless it absorbs heat which does not raid it’s temperature. This is know as latent heat of _________

Back 36

Vaporization

Front 37

A gas cannot become a liquid unless it gives off heat which does not lower its temperature.

This is latent heat of _________

Back 37

Condensation

Front 38

Liquid cannot become a gas unless it absorbs heat which does not change it’s temperature. This is know as latent heat of _________

Back 38

Vaporization

Front 39

A gas cannot become a liquid unless it gives off heat which does not lower its temperature.

This is latent heat of _________

Back 39

Condensation

Front 40

What is critical pressure?

Back 40

The highest temperature at which a gas can be liquified regardless of how much pressure is applied to it.

Front 41

The condition of both pressure and Temperature at which both liquid and vapour can exist in the same container simultaneously is called_____

Back 41

Saturation temperature

Front 42

What is critical pressure?

Back 42

Where a liquid will remain a liquid no matter how much heat is applied to it.

Front 43

What is the first law of thermodynamics?

Back 43

Energy can neither be created or destroyed , but can be converted from one type to another

Front 44

What is the first law of thermodynamics?

Back 44

Energy can neither be created or destroyed , but can be converted from one type to another

Front 45

Heat travels from a warm object to a cold one. This is the 2nd law of _________

Back 45

Thermodynamics

Front 46

What is the first law of thermodynamics?

Back 46

Energy can neither be created or destroyed , but can be converted from one type to another

Front 47

Heat travels from a warm object to a cold one. This is the 2nd law of _________

Back 47

Thermodynamics

Front 48

The heat required to change the temperature in a substance, but not it’s state is called :

Back 48

Sensible Heat.

Front 49

__________is the number of BTUs required to change the temperature of 1 pound of a substance by 1F .

Back 49

Specific Heat

Front 50

__________is the number of BTUs required to change the temperature of 1 pound of a substance by 1F .

Back 50

Specific Heat

Front 51

________is the amount of heat required to change the state of a substance

Back 51

Latent heat

Front 52

__________is the number of BTUs required to change the temperature of 1 pound of a substance by 1F .

Back 52

Specific Heat

Front 53

________is the amount of heat required to change the state of a substance

Back 53

Latent heat

Front 54

An equal amount of heat must be removed from the water at a constant temperature to make it to solid (latent heat of freezing). This same heat is also used to melt the ice and turn the solid into liquid. This is called the latent heat of

Back 54

Fusion

Front 55

__________is the number of BTUs required to change the temperature of 1 pound of a substance by 1F .

Back 55

Specific Heat

Front 56

________is the amount of heat required to change the state of a substance

Back 56

Latent heat

Front 57

An equal amount of heat must be removed from the water at a constant temperature to make it to solid (latent heat of freezing). This same heat is also used to melt the ice and turn the solid into liquid. This is called the latent heat of

Back 57

Fusion

Front 58

The amount of heat which must be added to change a substance from a solid to a vapour with no evidence of it going through the liquid state is called :

Back 58

Latent heat of sublimation

Front 59

__________is the number of BTUs required to change the temperature of 1 pound of a substance by 1F .

Back 59

Specific Heat

Front 60

________is the amount of heat required to change the state of a substance

Back 60

Latent heat

Front 61

An equal amount of heat must be removed from the water at a constant temperature to make it to solid (latent heat of freezing). This same heat is also used to melt the ice and turn the solid into liquid. This is called the latent heat of

Back 61

Fusion

Front 62

The amount of heat which must be added to change a substance from a solid to a vapour with no evidence of it going through the liquid state is called :

Back 62

Latent heat of sublimation

Front 63

Boiling point of a liquid is called

Back 63

Saturated vapour

Front 64

__________is the number of BTUs required to change the temperature of 1 pound of a substance by 1F .

Back 64

Specific Heat

Front 65

________is the amount of heat required to change the state of a substance

Back 65

Latent heat

Front 66

An equal amount of heat must be removed from the water at a constant temperature to make it to solid (latent heat of freezing). This same heat is also used to melt the ice and turn the solid into liquid. This is called the latent heat of

Back 66

Fusion

Front 67

The amount of heat which must be added to change a substance from a solid to a vapour with no evidence of it going through the liquid state is called :

Back 67

Latent heat of sublimation

Front 68

Boiling point of a liquid is called

Back 68

Saturated vapour

Front 69

Superheated vapour is vapour heated to a temperature above its _________

Back 69

Saturation point

Front 70

What is refrigerant R-718?

Back 70

Water