Previous NATE Heat Pump Service Practice Test 9

NATE_HEATPUMP_SERVICE NEC 2023

NATE Heat Pump Service Practice Test 10

A mixed scenario-based review combining reversing valves, defrost, auxiliary/emergency heat, balance point, efficiency, and refrigerant circuit diagnostics into realistic troubleshooting calls.

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NATE Heat Pump Service

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Frequently Asked Questions

Yes — completely free with no signup required. Every question includes a full explanation of the correct answer.

Two: the NATE Core exam plus at least one specialty exam (for example AC Service, Heat Pump Service, or Air Distribution Service). You can take them on the same day or separately.

The Core exam has 50 questions and each installation or service specialty exam has 100 questions. You need 70% on each to pass — 35 of 50 on Core and 70 of 100 on a specialty. Check natex.org for the current format before you book.

NATE certification lasts two years. To renew, you submit 16 hours of continuing education or retake the specialty exam before your certification expires.

No. These are independent practice tests written to match the published NATE exam topics. They are not official NATE exam questions.

Exam Tip: Scenario questions test whether you can apply the concept, not just recite it. Read the whole scenario before picking an answer.

30

Questions

30 min

Time

70%

Pass

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NATE Heat Pump Service Practice Test 10 — Question List

Question 1: A heat pump blows only cold air no matter what the thermostat is set to. What component is a strong first suspect?

The reversing valve, possibly stuck in the cooling position
The crankcase heater
The condensate drain line
The air filter only

Question 2: A heat pump blows only warm air no matter what the thermostat is set to. What component is a strong first suspect?

The condensate drain line
The reversing valve, possibly stuck in the heating position
The crankcase heater
The air filter only

Question 3: A heat pump seems to be stuck in defrost — the outdoor fan is off, the reversing valve is energized, and cold air is blowing indoors for an extended period. What should the technician check?

The thermostat batteries only
The condenser fan capacitor only
The defrost control board and its coil-temperature sensor, since defrost should terminate once the coil clears or after a maximum time
The indoor air filter only

Question 4: A customer says the system seems to heat and cool at the same time, with poor performance in both modes. What is a likely cause?

An internally leaking reversing valve allowing refrigerant to bypass between the high and low sides
A dirty air filter only
A miswired G terminal only
A weak run capacitor only

Question 5: A technician diagnoses a failed compressor and needs the customer to have heat while waiting for a part. What thermostat setting should the customer use in the meantime?

Cooling mode
Fan-only mode
Emergency heat, which bypasses the compressor and runs only the electric heat strips (or furnace on a dual-fuel system)
Auxiliary heat cannot be used without the compressor

Question 6: On a very cold day, a customer notices the heat pump runs constantly and auxiliary heat comes on frequently, but the house stays warm. Is this necessarily a malfunction?

Yes, this always indicates a failed compressor
Not necessarily — this can be normal operation below the system's balance point, where auxiliary heat is expected to help
Yes, this always indicates a refrigerant leak
Yes, this always indicates a reversing valve failure

Question 7: A heat pump delivers 10,000 watts of heat output while consuming 2,500 watts of electrical input. What is its COP?

2.5
1
25,000,000
4

Question 8: A customer asks which efficiency rating tells them about the heat pump's winter heating performance. What should the technician say?

SEER
HSPF — it measures seasonal heating efficiency
EER only
COP only, never a seasonal rating

Question 9: A heat pump sat without power for two days during a cold snap. What should the technician do before starting the compressor?

Start the compressor immediately to restore heat as fast as possible
Restore power and allow time for the crankcase heater to warm the oil before starting the compressor
Replace the compressor without further diagnosis
Skip the crankcase heater entirely since it has no real purpose

Question 10: On a dual-fuel system, the heat pump is running fine but the customer wants to know why the furnace never engages even in cold weather. Besides the switchover threshold, what else should be checked?

The furnace itself (ignition, gas supply, control board) in case it has a fault preventing it from ever engaging when called
Nothing else needs to be checked
Only the outdoor condenser fan needs to be checked
Only the indoor air filter needs to be checked

Question 11: A technician needs to measure subcooling but is unsure whether the system is in heating or cooling mode. Why does this matter before taking the reading?

Subcooling must be measured at the condenser outlet, and which coil is the condenser depends on the current mode
It does not matter — subcooling is always measured at the same coil
Subcooling cannot be measured on a heat pump under any circumstances
Mode only affects superheat, never subcooling

Question 12: A heat pump is asked to cool on an unseasonably cool 55°F day and performs poorly with unusually low head pressure. What system feature should the technician verify is working?

The crankcase heater
The low-ambient cooling control (fan-cycling pressure switch)
The emergency heat relay
The condensate drain line

Question 13: A technician installs a new thermostat on an unfamiliar heat pump and is unsure if it is an O-type or B-type system for the reversing valve. What should they do?

Guess O-type since it is most common in the US
Check that specific unit's wiring diagram to confirm which convention applies before finishing the installation
Wire both O and B together to be safe
Skip the reversing valve wire entirely

Question 14: During a normal defrost cycle, a customer notices the electric heat strips briefly turn on. Is this a malfunction?

Yes, this always indicates a stuck reversing valve
Yes, this always indicates a wiring fault
No — this is normal, since strips often energize during defrost so the customer is not blown with cold air while the system runs in cooling mode to melt frost
Yes, this always indicates the compressor has failed

Question 15: A heat pump's COP drops from 3.5 in mild weather to 1.8 on a very cold day. What does this change in COP reflect?

Less available heat in the colder outdoor air for the heat pump to extract, which is expected behavior, not necessarily a fault
This always proves the compressor has failed
COP never changes with outdoor temperature
This always proves the refrigerant charge is wrong

Question 16: A customer says they manually switched their thermostat to "Emergency Heat" because the outdoor unit was making a loud noise. What does this setting do?

It increases compressor speed to diagnose the noise
It bypasses the compressor entirely and runs only the backup heat strips (or furnace), which was the correct precaution given a suspected outdoor unit problem
It has no effect unless the thermostat is also rebooted
It permanently disables the heat pump

Question 17: On an O-type heat pump, during which mode is the reversing valve solenoid energized?

Heating mode
Cooling mode
It is always energized regardless of mode
It is never energized on an O-type system

Question 18: What is the "balance point" of a heat pump system?

The outdoor temperature at which the heat pump's heating capacity equals the building's heat loss
The exact temperature at which refrigerant freezes
The point at which the compressor reaches its maximum RPM
The indoor temperature setpoint only

Question 19: When is a compressor's crankcase heater typically energized?

Only while the compressor is actively running
Whenever the compressor is off and the disconnect is closed
Only during the defrost cycle
Only in cooling mode

Question 20: What two general strategies determine when a dual-fuel system switches from heat pump to furnace?

A fixed outdoor temperature threshold, or a cost-based comparison of the two fuel sources
The time of day only, in every case
The color of the thermostat display
The refrigerant charge level only

Question 21: A heat pump's outdoor coil is heavily iced and defrost cycles are not clearing it. What should the technician check, beyond the defrost control itself?

Refrigerant charge and airflow across the outdoor coil, since undercharge or airflow issues can cause excessive or ineffective frosting
Only the thermostat display brightness
Only the indoor blower speed setting
Nothing else needs to be checked

Question 22: A heat pump in cooling mode shows low superheat at the indoor coil. What does this suggest?

Possible undercharge only
Possible overcharge or evaporator flooding, the same as on any standard cooling system
This always means the reversing valve has failed
Low superheat cannot occur in cooling mode

Question 23: On a dual-fuel system, the technician observes both the compressor and the furnace burner energized at the same time during a routine heating call. What should be done?

Treat this as a control fault and investigate the dual-fuel control logic, since normal operation should generally run one source at a time
Do nothing, this is always normal
Immediately replace both the compressor and the furnace
Assume the thermostat batteries are the cause with no further checking

Question 24: How does a low-ambient cooling control differ from the balance point concept?

They are the exact same concept under two different names
Low-ambient control helps cooling mode work in cool weather; balance point is about heating mode capacity versus heat loss in cold weather
Balance point only applies to cooling mode
Low-ambient control only applies to heating mode

Question 25: A technician wants to verify refrigerant charge on a heat pump using superheat and subcooling. What is the recommended first step?

Put the system into cooling mode, since charging is commonly done and referenced in that mode for more stable readings
Only check charge during a defrost cycle
Charge can only be verified with the system off
Mode does not matter at all for charge verification

Question 26: Which measurement directly compares a heat pump's useful heat output to its electrical energy input at a given moment?

SEER
HSPF
COP (coefficient of performance)
Balance point

Question 27: How does the reversing valve participate in the defrost cycle?

It temporarily energizes to run the system in cooling mode, sending hot discharge gas to the outdoor coil to melt frost
The reversing valve has no role in defrost at all
It permanently switches the system to heating mode during defrost
It shuts off all refrigerant flow during defrost

Question 28: A heat pump in cooling mode shows high subcooling at the outdoor coil outlet. What does this suggest?

Possible undercharge only
This always means the reversing valve has failed
Possible overcharge or a liquid-line restriction, the same as on any standard cooling system
High subcooling cannot occur in cooling mode

Question 29: Why might a technician set a dual-fuel switchover point close to a heat pump's calculated balance point?

Because that is roughly where the heat pump alone starts falling short of the building's heating needs, making it a logical point to bring in the furnace
Balance point has no relationship to dual-fuel switchover at all
The balance point only applies to cooling mode
Switchover is always set at exactly 32°F regardless of the building

Question 30: A heat pump won't heat, the outdoor unit runs but blows cold air, and the customer says this started right after a power outage. What is a reasonable diagnostic order?

Replace the compressor immediately without further diagnosis
Check the reversing valve and its control signal first, since a stuck or miswired valve after a power event is a common, straightforward explanation
Assume the refrigerant has completely leaked out with no further checking
Assume the thermostat needs new batteries with no further checking

EXAM CARD NATE_HEATPUMP_SERVICE

Questions30

Time limit30 min

Pass score70%

Code editionNEC 2023

DifficultyIntermediate

Last reviewedJun 2026

Timer starts immediately. Progress is auto-saved.

Source: NEC 2026 (NFPA 70)