NATE Gas Heating Furnace Specialty Certification Exam Questions And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. Which type of furnace uses a heat exchanger to transfer heat from
combustion gases to the air?
A. Gas furnace
B. Electric furnace
C. Heat pump
D. Boiler
The heat exchanger in a gas furnace separates combustion gases from the
air being heated, transferring heat safely.
2. What is the primary function of the draft inducer in a gas furnace?
A. Mix gas and air
B. Ensure proper venting of combustion gases
C. Control blower speed
D. Regulate thermostat
The draft inducer creates a draft that pushes combustion gases out
through the venting system.
3. Which component ignites the gas in a modern gas furnace?
A. Thermostat
B. Ignitor
C. Draft inducer
NATE Gas2026
Rationales Heating
Q&A Furnace Specialty
| Instant Certification
Download Pdf Exam Questions And Correct Answers (Verified Answers) Plus
,NATE Gas Heating Furnace Specialty Certification Exam Questions And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
D. Flame sensor
The ignitor produces the spark or heat necessary to ignite the gas in the
burners.
4. What safety device shuts off the gas if the flame is not detected?
A. Thermocouple
B. Pressure switch
C. Draft inducer
D. Flame sensor
The flame sensor detects the presence of a flame and shuts off gas if no
flame is present, preventing unsafe gas buildup.
5. What is the purpose of the limit switch in a gas furnace?
A. Start the blower motor
B. Prevent overheating
C. Control gas pressure
D. Measure airflow
The limit switch opens to shut off the burners if the furnace exceeds a
safe temperature.
6. Which type of venting system is typically used for high-
efficiency condensing gas furnaces?
A. Chimney vent
B. B-Vent
C. PVC or CPVC vent
D. Metal flue only
High-efficiency condensing furnaces use plastic venting materials because
exhaust gases are cooler and can be safely vented through PVC.
NATE Gas2026
Rationales Heating
Q&A Furnace Specialty
| Instant Certification
Download Pdf Exam Questions And Correct Answers (Verified Answers) Plus
, NATE Gas Heating Furnace Specialty Certification Exam Questions And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
7. What is the main difference between a single-stage and a two-
stage gas furnace?
A. Blower speed
B. Burner operation levels
C. Type of gas used
D. Heat exchanger material
A single-stage furnace operates at full capacity, while a two-stage furnace
can operate at high or low output for efficiency.
8. Which component in a gas furnace detects pressure differences to
confirm inducer operation?
A. Flame sensor
B. Limit switch
C. Pressure switch
D. Thermostat
The pressure switch ensures that the inducer is running and venting
correctly before allowing the furnace to ignite.
9. What could cause a gas furnace to short cycle?
A. Dirty filter
B. Improper gas pressure
C. Oversized furnace
D. Thermostat placement
An oversized furnace heats the space too quickly, triggering the limit
switch and causing frequent on/off cycles.
10. Which fuel type is most commonly used in residential
gas furnaces in the U.S.?
A. Propane only
B. Natural gas
NATE Gas2026
Rationales Heating
Q&A Furnace Specialty
| Instant Certification
Download Pdf Exam Questions And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. Which type of furnace uses a heat exchanger to transfer heat from
combustion gases to the air?
A. Gas furnace
B. Electric furnace
C. Heat pump
D. Boiler
The heat exchanger in a gas furnace separates combustion gases from the
air being heated, transferring heat safely.
2. What is the primary function of the draft inducer in a gas furnace?
A. Mix gas and air
B. Ensure proper venting of combustion gases
C. Control blower speed
D. Regulate thermostat
The draft inducer creates a draft that pushes combustion gases out
through the venting system.
3. Which component ignites the gas in a modern gas furnace?
A. Thermostat
B. Ignitor
C. Draft inducer
NATE Gas2026
Rationales Heating
Q&A Furnace Specialty
| Instant Certification
Download Pdf Exam Questions And Correct Answers (Verified Answers) Plus
,NATE Gas Heating Furnace Specialty Certification Exam Questions And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
D. Flame sensor
The ignitor produces the spark or heat necessary to ignite the gas in the
burners.
4. What safety device shuts off the gas if the flame is not detected?
A. Thermocouple
B. Pressure switch
C. Draft inducer
D. Flame sensor
The flame sensor detects the presence of a flame and shuts off gas if no
flame is present, preventing unsafe gas buildup.
5. What is the purpose of the limit switch in a gas furnace?
A. Start the blower motor
B. Prevent overheating
C. Control gas pressure
D. Measure airflow
The limit switch opens to shut off the burners if the furnace exceeds a
safe temperature.
6. Which type of venting system is typically used for high-
efficiency condensing gas furnaces?
A. Chimney vent
B. B-Vent
C. PVC or CPVC vent
D. Metal flue only
High-efficiency condensing furnaces use plastic venting materials because
exhaust gases are cooler and can be safely vented through PVC.
NATE Gas2026
Rationales Heating
Q&A Furnace Specialty
| Instant Certification
Download Pdf Exam Questions And Correct Answers (Verified Answers) Plus
, NATE Gas Heating Furnace Specialty Certification Exam Questions And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
7. What is the main difference between a single-stage and a two-
stage gas furnace?
A. Blower speed
B. Burner operation levels
C. Type of gas used
D. Heat exchanger material
A single-stage furnace operates at full capacity, while a two-stage furnace
can operate at high or low output for efficiency.
8. Which component in a gas furnace detects pressure differences to
confirm inducer operation?
A. Flame sensor
B. Limit switch
C. Pressure switch
D. Thermostat
The pressure switch ensures that the inducer is running and venting
correctly before allowing the furnace to ignite.
9. What could cause a gas furnace to short cycle?
A. Dirty filter
B. Improper gas pressure
C. Oversized furnace
D. Thermostat placement
An oversized furnace heats the space too quickly, triggering the limit
switch and causing frequent on/off cycles.
10. Which fuel type is most commonly used in residential
gas furnaces in the U.S.?
A. Propane only
B. Natural gas
NATE Gas2026
Rationales Heating
Q&A Furnace Specialty
| Instant Certification
Download Pdf Exam Questions And Correct Answers (Verified Answers) Plus
