NATE Air-to-Air Heat Pump
Practice Test 1 – Exam
Questions & Verified Answers
(2026)
1. A refrigerant cylinder has a total weight of 36
lbs, with the empty cylinder weighing 6 lbs. One
technician uses one-sixth of the refrigerant, and
another removes 10 lbs afterward. How much
refrigerant remains?
15 lbs
2. What does a fan/limit control detect in a
furnace system?
Supply air temperature
3. In an oil burner, what ignites the atomized
fuel?
An electric arc between electrodes
4. Why are refrigerant leaks dangerous in
confined spaces?
They displace oxygen
,5. If an induced draft furnace pressure switch
fails to close, what is the most likely cause?
A blockage in the vent system
6. How do step-opening gas valves operate?
They open partially, then fully
7. What is the main purpose of a lockout function
in ignition controls?
Prevent buildup of unburned gas
8. Where should current be measured to properly
set a thermostat heat anticipator?
Between R and W terminals
9. What commonly causes flame lift in a natural
draft gas furnace?
Excessive gas pressure
10. What is the normal manifold pressure for a
natural gas furnace?
3–4 inches water column
11. Why is a drip leg installed in gas piping?
To trap contaminants before they reach the gas valve
,12. What is the proper manifold pressure for
propane systems?
At least 10 inches water column
13. How can a technician test auxiliary heat in a
heat pump?
By adjusting or bypassing outdoor thermostats
14. High discharge pressure during heating
startup is most likely caused by what issue?
Insufficient indoor airflow
15. After replacing a compressor during heating
season, what is the most accurate charging
method?
Weighing in the charge
16. During system startup, which indoor
adjustment is often overlooked?
Heat anticipator setting
17. A 5 kW electric heating element produces
approximately how much heat?
17,000 BTUs
18. Which instruments are used to calculate total
kilowatt usage in an electric furnace?
Ammeter and voltmeter
, 19. What is the function of a sequencer relay in
electric heating systems?
Reduce inrush current
20. What condition is most likely to cause
evaporator flooding in a capillary tube system?
Low airflow across the coil
21. How does an increase in latent heat load
affect system pressures?
Both suction and head pressures increase
22. What is the most effective way to evacuate
non-condensables from a system?
Connect the vacuum pump to both high and low
sides
23. Which condition indicates an overcharged
system with a fixed orifice?
High suction and high head pressure
24. What device provides the most accurate
control of refrigerant flow?
Thermostatic expansion valve
25. What is the most common cause of high
discharge pressure?
Dirty condenser coil
Practice Test 1 – Exam
Questions & Verified Answers
(2026)
1. A refrigerant cylinder has a total weight of 36
lbs, with the empty cylinder weighing 6 lbs. One
technician uses one-sixth of the refrigerant, and
another removes 10 lbs afterward. How much
refrigerant remains?
15 lbs
2. What does a fan/limit control detect in a
furnace system?
Supply air temperature
3. In an oil burner, what ignites the atomized
fuel?
An electric arc between electrodes
4. Why are refrigerant leaks dangerous in
confined spaces?
They displace oxygen
,5. If an induced draft furnace pressure switch
fails to close, what is the most likely cause?
A blockage in the vent system
6. How do step-opening gas valves operate?
They open partially, then fully
7. What is the main purpose of a lockout function
in ignition controls?
Prevent buildup of unburned gas
8. Where should current be measured to properly
set a thermostat heat anticipator?
Between R and W terminals
9. What commonly causes flame lift in a natural
draft gas furnace?
Excessive gas pressure
10. What is the normal manifold pressure for a
natural gas furnace?
3–4 inches water column
11. Why is a drip leg installed in gas piping?
To trap contaminants before they reach the gas valve
,12. What is the proper manifold pressure for
propane systems?
At least 10 inches water column
13. How can a technician test auxiliary heat in a
heat pump?
By adjusting or bypassing outdoor thermostats
14. High discharge pressure during heating
startup is most likely caused by what issue?
Insufficient indoor airflow
15. After replacing a compressor during heating
season, what is the most accurate charging
method?
Weighing in the charge
16. During system startup, which indoor
adjustment is often overlooked?
Heat anticipator setting
17. A 5 kW electric heating element produces
approximately how much heat?
17,000 BTUs
18. Which instruments are used to calculate total
kilowatt usage in an electric furnace?
Ammeter and voltmeter
, 19. What is the function of a sequencer relay in
electric heating systems?
Reduce inrush current
20. What condition is most likely to cause
evaporator flooding in a capillary tube system?
Low airflow across the coil
21. How does an increase in latent heat load
affect system pressures?
Both suction and head pressures increase
22. What is the most effective way to evacuate
non-condensables from a system?
Connect the vacuum pump to both high and low
sides
23. Which condition indicates an overcharged
system with a fixed orifice?
High suction and high head pressure
24. What device provides the most accurate
control of refrigerant flow?
Thermostatic expansion valve
25. What is the most common cause of high
discharge pressure?
Dirty condenser coil
