NATE Gas Heating (Air) Installation Technician
Certification Exam Questions and Answers
Latest 2026 Edition 100% Correct
1. Which component regulates the flow of gas into the burner?
a) Gas manifold
b) Draft inducer
c) Gas valve
d) Flame sensor
Rationale: The gas valve meters the correct amount of gas to the
burners for safe combustion.
2. What is the correct sequence of operation for a gas furnace?
a) Blower → Gas valve → Igniter → Burner
b) Thermostat call → Inducer motor → Igniter → Gas valve → Flame
→ Blower
c) Gas valve → Igniter → Flame sensor → Blower
d) Thermostat call → Blower → Gas valve → Igniter
Rationale: Proper sequence ensures safety and efficiency: call for
heat, draft established, ignition, flame detection, and airflow.
,3. The main purpose of a limit switch in a gas furnace is to:
a) Control blower speed
b) Prevent overheating of the heat exchanger
c) Regulate gas pressure
d) Measure room temperature
Rationale: The limit switch turns off the burner if the furnace
temperature exceeds safe limits.
4. A flame rollout switch is activated by:
a) Low gas pressure
b) Improper thermostat signal
c) Flame leaving the combustion chamber
d) Blower motor failure
Rationale: Flame rollout occurs when the flame is not properly
contained, triggering the safety switch.
5. What is the standard pressure for natural gas in residential
systems?
a) 3 psi
b) 10 psi
c) 7 inches of water column (≈0.25 psi)
d) 1 atm
Rationale: Residential natural gas is delivered at low pressure for
,safety and controlled combustion.
, 6. Which of the following materials is commonly used for venting high-
efficiency condensing furnaces?
a) Black steel
b) Aluminum
c) PVC or CPVC
d) Copper
Rationale: Condensing furnaces produce acidic condensate, requiring
corrosion-resistant PVC or CPVC venting.
7. What is the primary purpose of the blower in a gas furnace?
a) Ignite the gas
b) Control the gas valve
c) Distribute heated air through the ductwork
d) Remove combustion gases
Rationale: The blower circulates conditioned air from the furnace
into the home.
8. In a gas furnace, the flame sensor’s function is to:
a) Ignite the burners
b) Open the gas valve
c) Detect presence of a flame and allow the gas valve to remain open
d) Control blower operation
Rationale: The flame sensor ensures gas flows only when a flame is
Certification Exam Questions and Answers
Latest 2026 Edition 100% Correct
1. Which component regulates the flow of gas into the burner?
a) Gas manifold
b) Draft inducer
c) Gas valve
d) Flame sensor
Rationale: The gas valve meters the correct amount of gas to the
burners for safe combustion.
2. What is the correct sequence of operation for a gas furnace?
a) Blower → Gas valve → Igniter → Burner
b) Thermostat call → Inducer motor → Igniter → Gas valve → Flame
→ Blower
c) Gas valve → Igniter → Flame sensor → Blower
d) Thermostat call → Blower → Gas valve → Igniter
Rationale: Proper sequence ensures safety and efficiency: call for
heat, draft established, ignition, flame detection, and airflow.
,3. The main purpose of a limit switch in a gas furnace is to:
a) Control blower speed
b) Prevent overheating of the heat exchanger
c) Regulate gas pressure
d) Measure room temperature
Rationale: The limit switch turns off the burner if the furnace
temperature exceeds safe limits.
4. A flame rollout switch is activated by:
a) Low gas pressure
b) Improper thermostat signal
c) Flame leaving the combustion chamber
d) Blower motor failure
Rationale: Flame rollout occurs when the flame is not properly
contained, triggering the safety switch.
5. What is the standard pressure for natural gas in residential
systems?
a) 3 psi
b) 10 psi
c) 7 inches of water column (≈0.25 psi)
d) 1 atm
Rationale: Residential natural gas is delivered at low pressure for
,safety and controlled combustion.
, 6. Which of the following materials is commonly used for venting high-
efficiency condensing furnaces?
a) Black steel
b) Aluminum
c) PVC or CPVC
d) Copper
Rationale: Condensing furnaces produce acidic condensate, requiring
corrosion-resistant PVC or CPVC venting.
7. What is the primary purpose of the blower in a gas furnace?
a) Ignite the gas
b) Control the gas valve
c) Distribute heated air through the ductwork
d) Remove combustion gases
Rationale: The blower circulates conditioned air from the furnace
into the home.
8. In a gas furnace, the flame sensor’s function is to:
a) Ignite the burners
b) Open the gas valve
c) Detect presence of a flame and allow the gas valve to remain open
d) Control blower operation
Rationale: The flame sensor ensures gas flows only when a flame is
