Heat Pumps

Question 1

Are heat pumps designed to carry the entire heating load

Answer 1

Not in northern climates. They are sized to meet the cooling demands of a house.

Question 2

What is a miss matched system?

Answer 2

Different size condenser, and evaporator coils

Question 3

How do you determine the capacity of miss matched systems?

Answer 3

Take the outdoor coil rating and go 1000 BTUs in the direction of the Plenum coil rating

Question 4

What is a heat pump?

Answer 4

An AC that can work in reverse

Question 5

Outdoor coil acts as what in the summer and what in the winter

Answer 5

Condenser in the summer and evaporator in the winter

Question 6

Indoor coil acts as what in the summer and what did winter

Answer 6

Evaporator in the summer and condenser in the winter

Question 7

Can the heat pumps work with electric, gas or oil systems?

Answer 7

Electric. If heating is gas or oil, heat pump must shut off when furnace comes on.

Question 8

When can’t you test heat pumps?

Answer 8

During very cold weather, when pump is not working in the system is gas or oil

Question 9

Below a certain outdoor temperature, what happens to the heat pump?

Answer 9

It is locked out

Question 10

Don’t run cooling mode or heating mode above or below this temperature

Answer 10

65°F or 18°C

Question 11

Is a heat pump, air hotter or not as hot as air from gas or furnace

Answer 11

Not as hot

Question 12

What does a heat pump do if you can’t keep up to the furnace

Answer 12

Shut off and furnace starts

Question 13

Most thermostats with heat pumps have this feature

Answer 13

“ emergency heat” which bypass is heat pump

Question 14

How does ice up happen on a heat pump?

Answer 14

Outdoor air condenses water when it cools as it passes over the coil. Moisture falls out of the air as liquid (condensate) and freezes on the coil.

Question 15

What prevents ice up on heat pumps

Answer 15

Defrost cycle

Question 16

These heat pumps look the same as air conditioners

Answer 16

Air source

Question 17

Some systems use what to collect and dissipate heat

Answer 17

Ground or water

Question 18

How do ground source heat pumps collect or dissipate heat depending on the season

Answer 18

Horizontal or vertical pipes underground with liquid

Question 19

Some systems use what instead of looped piping

Answer 19

Two wells. Water is extracted from one and pumped into the other.

Question 20

Water source heat pumps use these

Answer 20

Rivers and lakes

Question 21

What is the advantage of ground/water source?

Answer 21

Warmer than outdoor air

Question 22

What is a bivalent heat pump?

Answer 22

Fools the heat pump by a burner outside below the coil that turns on when the system is about to shut down

Question 23

These heat pumps do not require a furnace

Answer 23

Bivalent, due to the auxiliary heater (burner)

Question 24

Do outdoor gas burners need a chimney

Answer 24

No

Question 25

Two types of heat pumps

Answer 25

Air to air Water to air (geothermal)

Question 26

Main difference between AC and heat pumps

Answer 26

Heat pumps have a reversing valve that changes the direction of refrigerant flow

Question 27

What does an accumulator do on a heat pump?

Answer 27

Keeps liquid refrigerant from entering compressor

Question 28

What controls refrigerant state that flows to coils?

Answer 28

Metering devices

Question 29

When inspecting heat pumps, how should you check them?

Answer 29

Use thermostat control only. No changing heating or cooling mode.

Question 30

Heat pumps should be energized how long before operation

Answer 30

24 hours

Question 31

Is air to water condenser inside or outside

Answer 31

Inside

Question 32

What temperatures will heat pumps work all the way down to?

Answer 32

0°F or -17°C

Question 33

What are the main differences of heat pumps compared AC?

Answer 33

Reversing valve Two throttling/expansion devices (capillaries) with check valves

Question 34

Does a heat pump or AC always have a heater on the compressor?

Answer 34

Heat pump always has heater on compressor. AC might but doesn’t have to.

Question 35

Why do heat pumps need to defrost cycle?

Answer 35

They can get frost on the coil outside

Question 36

Describe the defrost cycle

Answer 36

Switch heat pump to AC mode to mount frost. Electric treating element gets turned on inside coil.

Question 37

What does SEER stand for?

Answer 37

Seasonal energy, efficiency, ratio

Question 38

Examples of heaters with COP 1 ratings

Answer 38

(100% efficiency) Baseboard heater, blow dryer, space heater (purely resistive)

Question 39

Do heat pumps have good COP ratings

Answer 39

Yes. Above 1 but as temperature drops, so does COP.

Question 40

What is COP balance point?

Answer 40

Where heat pump can keep up. Below that, it needs make up heat.

Question 41

What does AFUE stand for?

Answer 41

Annual fuel utilization efficiency

Question 42

What is the AFUE number for electric heat?

Answer 42

There is none. (no fuel.) COP up to 4-5

Question 43

Geothermal (geoexchange) normally uses

Answer 43

Fluid

Question 44

Describe an open loop system

Answer 44

Wells/lake/river (hundred foot distance between wells)

Question 45

Describe a closed loop system

Answer 45

Piping run below frost line

Question 46

What does a bivalent system have?

Answer 46

Burner in the outdoor coil

Question 47

What is the difference of a triple split system?

Answer 47

Compressor indoors

Question 48

Where does the accumulator sit?

Answer 48

Between compressor and reversing valve (in suction line)

Question 49

When does the accumulator work the most?

Answer 49

Heating season (winter)

Question 50

Heating season= Cooling season =

Answer 50

Winter Summer

Question 51

In heat pumps, where does refrigerant go first after compressor

Answer 51

Reversing valve to direct flow Check valves let refrigerant bypass

Question 52

When does the outdoor fan stop?

Answer 52

Defrost cycle

Question 53

What could insufficient air be caused by

Answer 53

Blocked diffusers

Question 54

What is the problem with restricting airflow across the indoor coil? (Homeowners shutting off registers)

Answer 54

Raises discharge pressure, which raises compression ratio, which can ruin compressor

Question 55

Why should heat pumps be raised 12 inches off the ground

Answer 55

Water to exit underneath

Question 56

Antifreeze in colder climates for air to water heat pumps between these

Answer 56

Outdoor unit and heat exchanger

Question 57

What should be used in air to water heat pumps for high-volume systems? (radiant panels.)

Answer 57

Expansion tanks

Question 58

Zoned systems use these

Answer 58

Buffer tanks