Hvac 100 Final

Front 1

Molecular molecular motion stops at what degree Fahrenheit?

Back 1

C. -460

Front 2

The law of conservation states that energy can neither be ____ or ____.

Back 2

A. Created or destroyed

Front 3

The define a British Thermal unit. BTU

Back 3

The amount of heat required to raise the temperature of 1# of water 1℉ at sea level

Front 4

Heat flows naturally from a colder substance to a warmer substance

Back 4

False

Front 5

There are two kinds of heat, what are they?

Back 5

Sensible and latent heat

Front 6

What he is known as "hidden" heat?

Back 6

Latent heat

Front 7

What is atmospheric pressure at sea level?

Back 7

15 psi

Front 8

Temperature that can be measured is known as _____ heat.

Back 8

Sensible

Front 9

We take heat from where is not wanted release it where it doesn't matter, this describes the refrigeration process.

Back 9

True

Front 10

Matter exists in three states, name them:

Back 10

Gas, liquid and solid

Front 11

Electrical energy and heat energy are two forms of energy used in this industry

Back 11

True

Front 12

Vapor exerts pressure pressure in what direction?

Back 12

E. All of the above

Front 13

Water, because it is a liquid, pushes out in all directions including up.

Back 13

False

Front 14

The greater the temperature difference between two objects, the faster the heat transfer.

Back 14

True

Front 15

Refrigeration is the process of removing heat from a place where is not wanted and transferring the heat to a place where:

Back 15

C. It makes little or no difference

Front 16

What are three temperature ranges of refrigeration?

Back 16

Low temperature, medium temperature, and high temperature

Front 17

The evaporator in a refrigeration system is responsible for______ into the system from whatever medium it is to be cooled.

Back 17

Absorbing heat

Front 18

The evaporator is responsible for removing____ and _____heat

Back 18

B. Latent; sensible

Front 19

Dehumidifying the air means to remove the moisture.

Back 19

True.

Front 20

The evaporator must be_____ then the medium to be cooled to have a heat exchange.

Back 20

A. Cooler

Front 21

Refrigerant in the evaporator.......

Back 21

B. Changes from liquid to vapor

Front 22

The heat that is added to a vapor after all of the liquid has boiled off is referred to as______.

Back 22

C. Superheated

Front 23

When the evaporator experiences a heat-load increase, the suction pressure____.

Back 23

D. Increases

Front 24

Some evaporators have single circuit and some have multiple circuit

Back 24

True

Front 25

When the refrigerated space has been allowed to warm up considerably or is first started, this is called A _____ ______.

Back 25

D. Hot pulldown

Front 26

When the evaporator remove heat from there and lower the temperature, sensible heat is removed. When moisture is removed from the air,________is removed.

Back 26

A. Latent heat

Front 27

For heat to travel from a cool substance to A warm substance, work must be performed. The motor that drives the compressor in the refrigeration cycle does this work

Back 27

True

Front 28

There are four types of copper that are used, and refrigeration we use which one?

Back 28

B. L

Front 29

Copper rubbing is called ACR tubing and is sized by:

Back 29

C. Outside diameter (OD)

Front 30

ACR tubing is capped at both ends to:

Back 30

B. Keep it clean and dry

Front 31

When tubing is bundled together with a liquid line and insulated suction line, it is called

Back 31

C. Line set

Front 32

Brazing generally requires temperatures ranging from:

Back 32

D. 1205-1550℉

Front 33

In the lecture/ demonstration it was explained that in the field we use _____ silver, but in the classroom we will use 5% silver solder because our copper is clean and the solder is cheaper.

Back 33

15%

Front 34

Propane, butane, and air acetylene are OK to use according to John.

Back 34

False

Front 35

The acetylene (red tank) should have the regulation set at:

Back 35

C. 5-7 LBS

Front 36

The oxygen (green tank) should have the regulator set at:

Back 36

D. 7-10 LBS

Front 37

Neither the oxygen or the acetylene gauge should be set above 25 LBS.

Back 37

False

Front 38

ACR copper will not fit inside itself because of its diameters

Back 38

False

Front 39

The______is considered the heat of the system

Back 39

B. Compressor

Front 40

What is another term for the compressor?

Back 40

Vapor pump

Front 41

Overheated oil may turn to carbon and create ______ in the system.

Back 41

B. Acid

Front 42

Name the 5 major types of compressors used in the refrigeration and air conditioning industry.

Back 42

Reciprocal, centrifugal, screw, scroll, and rotary

Front 43

Name the two housing categories for reciprocal compressor

Back 43

Hermetic and open

Front 44

There are two types of hermetic compressors, what are they?

Back 44

Fully hermetic and semi hermetic

Front 45

The compressor that is sometimes referred to as a "tin can" is the semi hermetic and can be serviced in the field, if need be.

Back 45

False

Front 46

The serviceable hermetic that can be worked on in the field is called a:

Back 46

A. Semi hermetic

Front 47

There are two methods used to mount the compressor inside the shell;______ and______.

Back 47

C. Rigid mount and spring mount

Front 48

______ ______ protection devices and hermetic motors to check the motor from overheating. These devices are embedded in or near the windings.

Back 48

C. Internal motor

Front 49

Direct Drive and open drive belt compressors have a device for keeping the refrigerant from leaking out around the drive shaft, they are called:

Back 49

D. Shaft seals