NATE Heat Pumps 3

Question 1

What is a typical symptom of an overcharged heat pump during cooling mode?

Accepted Answer

High suction pressure and high discharge pressure

Answer

Low suction pressure and low discharge pressure

Answer

Low suction pressure and high discharge pressure

Answer

Normal pressures but high superheat

Question 2

During defrost mode, why does the indoor electric heat strip energize?

Accepted Answer

To temper the cool air being delivered while the system is in cooling mode for defrost

Answer

To prevent the compressor from overheating

Answer

To boost system capacity in cold weather

Answer

To prevent the outdoor coil from freezing

Question 3

A heat pump's outdoor unit is making a hissing noise and the reversing valve solenoid is energized. What is the most likely cause?

Accepted Answer

Reversing valve internal bypass (leaking internally)

Answer

Overcharged refrigerant system

Answer

Refrigerant leak at the reversing valve

Answer

Defrost board failure

Question 4

What is the recommended method for charging a heat pump system in heating mode?

Accepted Answer

Charge by subcooling measured at the outdoor coil liquid line

Answer

Charge by sight glass clarity

Answer

Charge by suction superheat at the indoor coil

Answer

Charge by outdoor ambient temperature chart

Question 5

Which component on a heat pump prevents refrigerant from backing up into the compressor during the off cycle?

Accepted Answer

Accumulator

Answer

Reversing valve

Answer

Check valve

Answer

Filter drier

Question 6

What is a dual-fuel heat pump system?

Accepted Answer

A heat pump paired with a gas furnace that automatically switches to gas heat below a set outdoor temperature

Answer

A heat pump that uses both R-410A and R-32 refrigerants

Answer

A system with two compressors for redundancy

Answer

A heat pump that can use solar and grid electricity