NATE AIR CONDITIONING AND HEAT
PUMPS 2025 EXAM STUDYGUIDE
QUESTIONS AND DETAILED CORRECT
ANSWERS | A+ GRADE
Heat pump compressors sometimes run hotter than
compressors used in cooling-only units because heat
pump compressors ____.
a. exhibit low refrigerant density at low suction pressures
during the heating cycle
b. pump liquid refrigerant during the cooling cycle
c. must prevent ice formation during the defrost cycle
d. must heat indoor spaces in the winter Correct Answer a
(exhibit low refrigerant density at low suction)
When is a crankcase heater most needed?
a. Early in the morning during the cooling cycle
b. When the compressor is operating in very cold winter
weather
c. When the compressor is operating in very humid
conditions
d. When the compressor is off Correct Answer d (When
the compressor is off)
Work done on the refrigerant in the condenser is
transferred as ____.
,a. latent heat
b. sensible heat
c. specific heat
d. both sensible and latent heat Correct Answer d (both
sensible and latent heat)
Why are more circuits needed in the outdoor coils used in
heat pumps than in the condenser coils used in cooling-
only units?
a. To keep the pressure drop across the outdoor coil high
b. To keep the pressure drop across the outdoor coil low
c. To provide more subcooling during the cooling cycle
d. To provide more subcooling during the heating cycle
Correct Answer b (To keep the pressure drop across the
outdoor coil low)
What is the typical water flow rate per ton of cooling for
water-source heat pumps operating in closed-loop
systems?
a. 3.0 gpm per ton
b. 2.5 gpm per ton
c. 2.0 gpm per ton
d. 1.5 gpm per ton Correct Answer a (3.0 gpm per ton)
What tool should be used to shorten a capillary tube?
a. A pair of pliers with side-cutter edges
b. A small tubing cutter
c. Any tubing cutter approved for use on refrigerant tubing
,d. A triangular or knife-edge file Correct Answer d (A
triangular or knife-edge file)
Which pressure in a TEV is the opening pressure?
a. Bulb pressure
b. Evaporator pressure
c. Spring pressure
d. A combination of bulb and spring pressures Correct
Answer a (Bulb pressure)
What affect does a low refrigerant charge have on
reversing valve operation?
a. It causes the slider to overheat
b. It creates a hissing sound in the reversing valve
c. It increases the chance that the reversing valve will not
be able to transfer properly
d. It has no effect on reversing valve operation Correct
Answer c (It increases the chance that the reversing valve
will not be able to transfer properly)
When adding a heat pump to an existing fossil-fuel
furnace, an installer must do all of the following except
____.
a. add a control to prevent the heat pump and furnace
from operating at the same time during normal heating
b. confirm there is adequate clearance around the outdoor
section for good air flow
, c. level the indoor coil's condensate pan to ensure proper
drainage of condensate water
d. make sure that the number of fins per inch of the new
coils equals that of the replaced coils Correct Answer d
(make sure that the number of fins per inch of the new
coils equals that of the replaced coils)
What is the purpose of a receiver?
a. It prevents liquid refrigerant from slugging the
compressor
b. It removes heat from refrigerant vapor
c. It returns oil to the compressor at a rate the compressor
can tolerate
d. It stores liquid refrigerant Correct Answer d (It stores
liquid refrigerant)
What is the typical storage life of modern refrigerants?
a. 5 to 10 years
b. 10 to 20 years
c. 20 to 30 years
d. Modern refrigerants have an indefinite storage life
Correct Answer d (Modern refrigerants have an indefinite
storage life)
Which of the following should be used to leak-test
refrigerant tubing?
a. Compressed air
b. Dry nitrogen
PUMPS 2025 EXAM STUDYGUIDE
QUESTIONS AND DETAILED CORRECT
ANSWERS | A+ GRADE
Heat pump compressors sometimes run hotter than
compressors used in cooling-only units because heat
pump compressors ____.
a. exhibit low refrigerant density at low suction pressures
during the heating cycle
b. pump liquid refrigerant during the cooling cycle
c. must prevent ice formation during the defrost cycle
d. must heat indoor spaces in the winter Correct Answer a
(exhibit low refrigerant density at low suction)
When is a crankcase heater most needed?
a. Early in the morning during the cooling cycle
b. When the compressor is operating in very cold winter
weather
c. When the compressor is operating in very humid
conditions
d. When the compressor is off Correct Answer d (When
the compressor is off)
Work done on the refrigerant in the condenser is
transferred as ____.
,a. latent heat
b. sensible heat
c. specific heat
d. both sensible and latent heat Correct Answer d (both
sensible and latent heat)
Why are more circuits needed in the outdoor coils used in
heat pumps than in the condenser coils used in cooling-
only units?
a. To keep the pressure drop across the outdoor coil high
b. To keep the pressure drop across the outdoor coil low
c. To provide more subcooling during the cooling cycle
d. To provide more subcooling during the heating cycle
Correct Answer b (To keep the pressure drop across the
outdoor coil low)
What is the typical water flow rate per ton of cooling for
water-source heat pumps operating in closed-loop
systems?
a. 3.0 gpm per ton
b. 2.5 gpm per ton
c. 2.0 gpm per ton
d. 1.5 gpm per ton Correct Answer a (3.0 gpm per ton)
What tool should be used to shorten a capillary tube?
a. A pair of pliers with side-cutter edges
b. A small tubing cutter
c. Any tubing cutter approved for use on refrigerant tubing
,d. A triangular or knife-edge file Correct Answer d (A
triangular or knife-edge file)
Which pressure in a TEV is the opening pressure?
a. Bulb pressure
b. Evaporator pressure
c. Spring pressure
d. A combination of bulb and spring pressures Correct
Answer a (Bulb pressure)
What affect does a low refrigerant charge have on
reversing valve operation?
a. It causes the slider to overheat
b. It creates a hissing sound in the reversing valve
c. It increases the chance that the reversing valve will not
be able to transfer properly
d. It has no effect on reversing valve operation Correct
Answer c (It increases the chance that the reversing valve
will not be able to transfer properly)
When adding a heat pump to an existing fossil-fuel
furnace, an installer must do all of the following except
____.
a. add a control to prevent the heat pump and furnace
from operating at the same time during normal heating
b. confirm there is adequate clearance around the outdoor
section for good air flow
, c. level the indoor coil's condensate pan to ensure proper
drainage of condensate water
d. make sure that the number of fins per inch of the new
coils equals that of the replaced coils Correct Answer d
(make sure that the number of fins per inch of the new
coils equals that of the replaced coils)
What is the purpose of a receiver?
a. It prevents liquid refrigerant from slugging the
compressor
b. It removes heat from refrigerant vapor
c. It returns oil to the compressor at a rate the compressor
can tolerate
d. It stores liquid refrigerant Correct Answer d (It stores
liquid refrigerant)
What is the typical storage life of modern refrigerants?
a. 5 to 10 years
b. 10 to 20 years
c. 20 to 30 years
d. Modern refrigerants have an indefinite storage life
Correct Answer d (Modern refrigerants have an indefinite
storage life)
Which of the following should be used to leak-test
refrigerant tubing?
a. Compressed air
b. Dry nitrogen
