Heat Pump

Question 1

Which of the following factors affect a customers comfort? 
A)air movement 
B)humidity 
C)temperature 
D)all of the above

Answer 1

All of the above

Question 2

A cooling load calculation estimates the sensible heat gain of a structure. The maximum sensible capacity of a cooling-only system should be within _________% of this calculated value.

Answer 2

+15%

Question 3

The maximum sensible cooling capacity of a heat pump should be within ____________% of the calculated sensible heat gain of a structure with a large heating load.

Answer 3

+25%

Question 4

The combined output of a heat pump and its auxiliary heat should not exceed the calculated heat loss of a home by more than _________٪

Answer 4

15 %

Question 5

What amount of auxiliary electric heat is needed when the output of a heat pump on a design day equals 18,800 Btuh and the heat loss of a home is 29,700 Btuh?

Answer 5

3.2kwh

Question 6

The 3 processes the transfer heat energy are conduction, convection and __________.

Answer 6

Radiation

Question 7

Heat transfer that occurs when substances of different temperatures are in contact with each other is called ______________.

Answer 7

Conduction

Question 8

What effect does raising the pressure in a sealed system have on refrigerant.

Answer 8

The refrigerant’s boiling point increases

Question 9

What is the primary danger to people near and accidental refrigerant release or spill?

Answer 9

Suffocation calls by the heavier refrigerant displacing oxygen in the air.

Question 10

The maximum temperature at which refrigerant may be stored is _________Fahrenheit when the container is no more than __________%full of liquid by volume.

Answer 10

125°, 80%

Question 11

Boiling of the refrigerant occurs in which system component.

Answer 11

Evaporator

Question 12

Why is super heat necessary in a system that utilizes hermetic compressors.

Answer 12

It ensures that dry vapor reaches the compressor so that mechanical damage does not occur

Question 13

When the heat load on an evaporator increases, what is the effect on the system?

Answer 13

Suction pressure and discharge pressure both increase

Question 14

What type of energy is transferred when work is done In the condenser.

Answer 14

Both latent and sensible heat energy

Question 15

What is the primary function performed by a thermal expansion valve

Answer 15

It maintains the Correct superheat in the suction vapor leaving the evaporator.

Question 16

Which component pumps refrigerant through the system and raises the vapor temperature

Answer 16

Compressor

Question 17

How are hermetic compressors motors cooled

Answer 17

With suction vapor drawn from the evaporator.

Question 18

Heat pump compressors sometimes run hotter then compressors used in cooling‐ only units because heat pumps compressors _______.

Answer 18

Exhibit low refrigerant density at low suction pressures during the heating cycle

Question 19

When is crankcase heat most needed.

Answer 19

When the compressor is off

Question 20

Work done on the refrigerate in the condenser is transferred as______.

Answer 20

Both sensible and latent heat

Question 21

Why are more circuits needed in the outdoor coils used in heat pumps than in the condenser coil used in the cooling only units?

Answer 21

To keep the pressure drop across the outdoor coil low

Question 22

What is the typical water flow rate per ton of cooling for a water source heat pumps operating in closed loop systems?

Answer 22

3 gpm

Question 23

What tool should be used to shorten a capillary tube

Answer 23

A triangular or knife edge file

Question 24

Which pressure in A TEV is the operating pressure

Answer 24

Bulb pressure

Question 25

What effect does a low refrigerant charge have on reversing valve operation

Answer 25

It increases the chance that the reversing valve will not be able to transfer properly

Question 26

When adding a heat pump to an existing fossil fuel furnace and installer must do all of the following except

Answer 26

Make sure that the number of fins per inch of the new coil equal that of the replaced coils

Question 27

What is the purpose of a receiver

Answer 27

It stores liquid refrigerant

Question 28

What is the typical storage life of modern refrigerant

Answer 28

Modern refrigerant’s have in indefinite storage life

Question 29

Which of the following should be used to leak test refrigerant Tubing

Answer 29

Dry nitrogen