1|Page
North American Technician Excellence (NATE)
Specialty Heat Pump Exam | Latest Verified
Questions and Detailed Answers
OVERVIEW DESCRIPTION
This Comprehensive set of multiple choice questions is designed for the North
American Technician Excellence (NATE) Specialty Heat Pump Exam, which validates a
technician's expertise in installing, servicing, maintaining, and repairing air-to-air heat
pump systems up to 30 tons. The questions cover the exam's four key areas—Service,
System Components, Installation, and Applied Knowledge—and address essential
topics such as the refrigerant circuit and components, troubleshooting using electrical
and pressure/temperature measurements, defrost cycle management, proper
installation and start-up procedures, and system operation. Updated to reflect the 2026
curriculum, the content also integrates decarbonization principles supported by the
U.S. Department of Energy, emphasizing high-efficiency heat pump technology and its
role in reducing carbon emissions.
QUESTION 1
A heat pump operating in heating mode has a measured suction pressure of 45 psig at
the compressor inlet (R-410A) and a suction line temperature of 32°F. The outdoor
ambient is 35°F. Approximately what is the suction superheat?
A. 0°F
B. 10°F
C. 22°F
D. 32°F
CORRECT ANSWER: B
EXPERT RATIONALE: R-410A at 45 psig has a saturation temperature of approximately
22°F. Suction line temperature of 32°F minus 22°F gives 10°F superheat, which is a
healthy level indicating a fully vapor refrigerant entering the compressor.
,2|Page
QUESTION 2
A heat pump condenser fan motor in cooling mode runs intermittently and overheats.
The technician measures 215 V across the motor while it's off and 180 V when running,
rated for 208/230 V. What is the most likely cause?
A. Shorted run capacitor
B. Open start winding
C. High-resistance connection in the circuit
D. Undersized contactor
CORRECT ANSWER: C
EXPERT RATIONALE: Voltage drop from 215 V to 180 V under load indicates excessive
resistance in the power circuit, such as a corroded connection or loose wire. This causes
lower voltage, leading to motor overheating and intermittent operation.
QUESTION 3
During a heat pump heating cycle, the indoor coil’s entering air temperature is 68°F and
leaving air temperature is 88°F with an airflow of 1,200 CFM. Using the sensible heat
formula (BTU/hr = 1.08 × CFM × ΔT), approximately how many BTUs per hour is the
heat pump delivering?
A. 14,400
B. 25,920
C. 31,104
D. 86,400
CORRECT ANSWER: B
EXPERT RATIONALE: ΔT = 88°F – 68°F = 20°F. 1.08 × 1200 × 20 = 25,920 BTU/hr. This
formula calculates sensible heat output and is used to verify capacity.
,3|Page
QUESTION 4
The reversing valve in a heat pump fails to shift from heating to cooling. With the
system off, the technician measures 24 V between the O/B terminal and common at the
thermostat. In cooling mode, the thermostat energizes the O terminal. The solenoid coil
resistance measures 18 Ω. What is the next step?
A. Replace the thermostat
B. Check for 24 V at the solenoid coil during a cooling call
C. Replace the reversing valve body
D. Add a hard-start kit
CORRECT ANSWER: B
EXPERT RATIONALE: First confirm that the control voltage is reaching the reversing valve
coil under a call. If 24 V is present at the coil and it's not shifting, the coil or valve may
be faulty; measuring voltage under load eliminates control wiring issues.
QUESTION 5
In a heat pump with a scroll compressor, the technician hears a loud rattling noise
immediately after installation and notices the suction line is hot and discharge line cool.
What is the most likely cause?
A. Overcharge of refrigerant
B. Reversing valve stuck in heating
C. Compressor running in reverse rotation
D. Defective compressor internal bypass
CORRECT ANSWER: C
EXPERT RATIONALE: A three-phase scroll compressor running backwards produces a
loud noise, hot suction, and poor pumping. Reversing any two power leads will correct
rotation; single-phase scrolls check proper phasing.
, 4|Page
QUESTION 6
A heat pump defrost cycle is initiated by which of the following?
A. High indoor coil temperature
B. Outdoor coil thermistor sensing frost and time accumulator
C. Low suction pressure for 30 minutes
D. Difference between outdoor and indoor temperature > 30°F
CORRECT ANSWER: B
EXPERT RATIONALE: Demand-defrost controls use an outdoor coil temperature sensor
combined with a timed accumulated compressor run-time to initiate defrost only when
frost formation actually reduces coil efficiency.
QUESTION 7
For proper condensate runoff during defrost, the outdoor unit must be installed:
A. Level in all directions
B. Slightly tilted toward the compressor
C. Elevated with free space underneath and a drain path
D. Recessed below grade
CORRECT ANSWER: C
EXPERT RATIONALE: Outdoor units need to be elevated above snow accumulation and
provide clear space below for melted frost to drain away, preventing ice buildup that
can damage the coil.
QUESTION 8
In heat pump cooling mode, the liquid line temperature is 105°F and the liquid line
pressure is 360 psig (R-410A). What is the subcooling?
A. 5°F
B. 10°F
North American Technician Excellence (NATE)
Specialty Heat Pump Exam | Latest Verified
Questions and Detailed Answers
OVERVIEW DESCRIPTION
This Comprehensive set of multiple choice questions is designed for the North
American Technician Excellence (NATE) Specialty Heat Pump Exam, which validates a
technician's expertise in installing, servicing, maintaining, and repairing air-to-air heat
pump systems up to 30 tons. The questions cover the exam's four key areas—Service,
System Components, Installation, and Applied Knowledge—and address essential
topics such as the refrigerant circuit and components, troubleshooting using electrical
and pressure/temperature measurements, defrost cycle management, proper
installation and start-up procedures, and system operation. Updated to reflect the 2026
curriculum, the content also integrates decarbonization principles supported by the
U.S. Department of Energy, emphasizing high-efficiency heat pump technology and its
role in reducing carbon emissions.
QUESTION 1
A heat pump operating in heating mode has a measured suction pressure of 45 psig at
the compressor inlet (R-410A) and a suction line temperature of 32°F. The outdoor
ambient is 35°F. Approximately what is the suction superheat?
A. 0°F
B. 10°F
C. 22°F
D. 32°F
CORRECT ANSWER: B
EXPERT RATIONALE: R-410A at 45 psig has a saturation temperature of approximately
22°F. Suction line temperature of 32°F minus 22°F gives 10°F superheat, which is a
healthy level indicating a fully vapor refrigerant entering the compressor.
,2|Page
QUESTION 2
A heat pump condenser fan motor in cooling mode runs intermittently and overheats.
The technician measures 215 V across the motor while it's off and 180 V when running,
rated for 208/230 V. What is the most likely cause?
A. Shorted run capacitor
B. Open start winding
C. High-resistance connection in the circuit
D. Undersized contactor
CORRECT ANSWER: C
EXPERT RATIONALE: Voltage drop from 215 V to 180 V under load indicates excessive
resistance in the power circuit, such as a corroded connection or loose wire. This causes
lower voltage, leading to motor overheating and intermittent operation.
QUESTION 3
During a heat pump heating cycle, the indoor coil’s entering air temperature is 68°F and
leaving air temperature is 88°F with an airflow of 1,200 CFM. Using the sensible heat
formula (BTU/hr = 1.08 × CFM × ΔT), approximately how many BTUs per hour is the
heat pump delivering?
A. 14,400
B. 25,920
C. 31,104
D. 86,400
CORRECT ANSWER: B
EXPERT RATIONALE: ΔT = 88°F – 68°F = 20°F. 1.08 × 1200 × 20 = 25,920 BTU/hr. This
formula calculates sensible heat output and is used to verify capacity.
,3|Page
QUESTION 4
The reversing valve in a heat pump fails to shift from heating to cooling. With the
system off, the technician measures 24 V between the O/B terminal and common at the
thermostat. In cooling mode, the thermostat energizes the O terminal. The solenoid coil
resistance measures 18 Ω. What is the next step?
A. Replace the thermostat
B. Check for 24 V at the solenoid coil during a cooling call
C. Replace the reversing valve body
D. Add a hard-start kit
CORRECT ANSWER: B
EXPERT RATIONALE: First confirm that the control voltage is reaching the reversing valve
coil under a call. If 24 V is present at the coil and it's not shifting, the coil or valve may
be faulty; measuring voltage under load eliminates control wiring issues.
QUESTION 5
In a heat pump with a scroll compressor, the technician hears a loud rattling noise
immediately after installation and notices the suction line is hot and discharge line cool.
What is the most likely cause?
A. Overcharge of refrigerant
B. Reversing valve stuck in heating
C. Compressor running in reverse rotation
D. Defective compressor internal bypass
CORRECT ANSWER: C
EXPERT RATIONALE: A three-phase scroll compressor running backwards produces a
loud noise, hot suction, and poor pumping. Reversing any two power leads will correct
rotation; single-phase scrolls check proper phasing.
, 4|Page
QUESTION 6
A heat pump defrost cycle is initiated by which of the following?
A. High indoor coil temperature
B. Outdoor coil thermistor sensing frost and time accumulator
C. Low suction pressure for 30 minutes
D. Difference between outdoor and indoor temperature > 30°F
CORRECT ANSWER: B
EXPERT RATIONALE: Demand-defrost controls use an outdoor coil temperature sensor
combined with a timed accumulated compressor run-time to initiate defrost only when
frost formation actually reduces coil efficiency.
QUESTION 7
For proper condensate runoff during defrost, the outdoor unit must be installed:
A. Level in all directions
B. Slightly tilted toward the compressor
C. Elevated with free space underneath and a drain path
D. Recessed below grade
CORRECT ANSWER: C
EXPERT RATIONALE: Outdoor units need to be elevated above snow accumulation and
provide clear space below for melted frost to drain away, preventing ice buildup that
can damage the coil.
QUESTION 8
In heat pump cooling mode, the liquid line temperature is 105°F and the liquid line
pressure is 360 psig (R-410A). What is the subcooling?
A. 5°F
B. 10°F
