1|Page
NATE Gas Heat Practice Guide (NEW UPDATED VERSION) LATEST
ACTUAL EXAM QUESTIONS AND CORRECT ANSWERS (VERIFIED
QUESTIONS AND ANSWERS)- GUARANTEED PASS A+ UPDATED 2026
What precautions are required when mounting any gas furnace on a wood
platform in an attic? - CORRECT ANSWER ✔✔✔✔✔ None
QUESTION : The gas control valve may be damaged if exposed to an inlet
pressure above what? - CORRECT ANSWER ✔✔✔✔✔ 14 inch W.C.
QUESTION : How many elbows and joints should a vent connector have? -
CORRECT ANSWER ✔✔✔✔✔ As few as possible to reduce resistance of
flue gases.
QUESTION : Under what conditions, if any may the technician route the
exhaust of the furnace into the exhaust vent of the water heater: - CORRECT
ANSWER ✔✔✔✔✔ Under no conditions may you use the water heater
exhaust vent.
QUESTION : How may a technician terminate the intake and exhaust for proper
operation of a high efficiency gas furnace when using scheduled 40 PVC pipe: -
CORRECT ANSWER ✔✔✔✔✔ By using the specific manufacturers
termination kit or make one to meet their requirements.
2026 2027 GRADED A+
,2|Page
QUESTION : When suspended with metal strap and no saddle, flexible duct
should be: - CORRECT ANSWER ✔✔✔✔✔ supported with a minimum
strap width of
1/2".
QUESTION : A technician is installing a gas furnace and the customer has
decided not to install an air conditioner. Making this decision, the affect it will
have on the installation of the supply ductwork is: - CORRECT ANSWER
✔✔✔✔✔ Leave adequate space should be allowed for addition of a coil in the
future when feasible.
QUESTION : Leveling of a Mercury bulb is __________ - CORRECT
ANSWER ✔✔✔✔✔ Critical
QUESTION : Spray-type atomizing humidifiers are installed to do what? -
CORRECT ANSWER ✔✔✔✔✔ Discharge moisture into the supply duct.
QUESTION : Electronic air cleaners (EAC) installed in a gas furnace system
should be wired so they: - CORRECT ANSWER ✔✔✔✔✔ Only operate
any time the EAC On-Off switch is turned to ON.
QUESTION : The LP gas manifold pressure is commonly what? - CORRECT
ANSWER ✔✔✔✔✔ 10 to 11 in. W.C.
QUESTION : The polarity of a 120V gas furnace equipped with electronic flame
rectification is important because: - CORRECT ANSWER ✔✔✔✔✔ The
ignition control may not prove flame.
2026 2027 GRADED A+
,3|Page
QUESTION : Using a voltmeter, a technician can determine voltage drop at a gas
furnace: - CORRECT ANSWER ✔✔✔✔✔ With the furnace not operating
and then with the furnace operating.
QUESTION : The setting on a 4 speed PSC blower motor can be changed by
changing the: - CORRECT ANSWER ✔✔✔✔✔ Motor tap connection.
QUESTION : When starting up a dual system, the temperature rise method for
determining airflow cannot be used with compressor cycle of the heat pump
because: - CORRECT ANSWER ✔✔✔✔✔ The capacity of the system
varies too much with outdoor temperature.
QUESTION : The flame pattern a technician would expect to see on a properly
operating single stage gas furnace equipped with "in shot" type burner is a: -
CORRECT ANSWER ✔✔✔✔✔ Hard and forceful flame with a light blue
appearance and little or no yellow.
QUESTION : What is recommended method for a pressurization leak test of a
fuel gas pipe? - CORRECT ANSWER ✔✔✔✔✔ Compressed air
QUESTION : What is a diaphragm type differential pressure gauge used for? -
CORRECT ANSWER ✔✔✔✔✔ Measure air pressure.
QUESTION : The pressure reading on a manometer is expressed in: -
CORRECT ANSWER ✔✔✔✔✔ Inches of water.
2026 2027 GRADED A+
, 4|Page
QUESTION : A technician measures the return air temperature of a 100,000 BTU
output gas furnace to be 65°F and the supply side air temperature is 135°F.
Calculate the CFM. - CORRECT ANSWER ✔✔✔✔✔ The CFM would be
1323.
QUESTION : A dirty or clogged air filter in an operating gas furnace can cause
what? - CORRECT ANSWER ✔✔✔✔✔ Increase temperature rise.
QUESTION : What can bent vanes on a direct drive blower wheel in a gas
furnace cause? - CORRECT ANSWER ✔✔✔✔✔ Loss in airflow, excessive
blower motor wear, and increase noise.
QUESTION : A gas clothes dryer can interfere with the operation of a nearby
natural draft gas furnace with an atmospheric burner by: - CORRECT
ANSWER ✔✔✔✔✔ Stealing combustion air preventing complete fuel
burning.
QUESTION : During a preventive maintenance check of a gas furnace, what
should always be checked for on the ductwork? - CORRECT ANSWER
✔✔✔✔✔ Ductwork should always be checked for leaks and damage.
QUESTION : When performing a cycle check during a preventive maintenance
call, the technician should: - CORRECT ANSWER ✔✔✔✔✔ ~First check
with the owner of the equipment for their opinion of performance.
~The next step is to turn the unit off at the thermostat system switch. ~Next the
technician should set the FAN switch to ON and check that the blower is
running.
2026 2027 GRADED A+
NATE Gas Heat Practice Guide (NEW UPDATED VERSION) LATEST
ACTUAL EXAM QUESTIONS AND CORRECT ANSWERS (VERIFIED
QUESTIONS AND ANSWERS)- GUARANTEED PASS A+ UPDATED 2026
What precautions are required when mounting any gas furnace on a wood
platform in an attic? - CORRECT ANSWER ✔✔✔✔✔ None
QUESTION : The gas control valve may be damaged if exposed to an inlet
pressure above what? - CORRECT ANSWER ✔✔✔✔✔ 14 inch W.C.
QUESTION : How many elbows and joints should a vent connector have? -
CORRECT ANSWER ✔✔✔✔✔ As few as possible to reduce resistance of
flue gases.
QUESTION : Under what conditions, if any may the technician route the
exhaust of the furnace into the exhaust vent of the water heater: - CORRECT
ANSWER ✔✔✔✔✔ Under no conditions may you use the water heater
exhaust vent.
QUESTION : How may a technician terminate the intake and exhaust for proper
operation of a high efficiency gas furnace when using scheduled 40 PVC pipe: -
CORRECT ANSWER ✔✔✔✔✔ By using the specific manufacturers
termination kit or make one to meet their requirements.
2026 2027 GRADED A+
,2|Page
QUESTION : When suspended with metal strap and no saddle, flexible duct
should be: - CORRECT ANSWER ✔✔✔✔✔ supported with a minimum
strap width of
1/2".
QUESTION : A technician is installing a gas furnace and the customer has
decided not to install an air conditioner. Making this decision, the affect it will
have on the installation of the supply ductwork is: - CORRECT ANSWER
✔✔✔✔✔ Leave adequate space should be allowed for addition of a coil in the
future when feasible.
QUESTION : Leveling of a Mercury bulb is __________ - CORRECT
ANSWER ✔✔✔✔✔ Critical
QUESTION : Spray-type atomizing humidifiers are installed to do what? -
CORRECT ANSWER ✔✔✔✔✔ Discharge moisture into the supply duct.
QUESTION : Electronic air cleaners (EAC) installed in a gas furnace system
should be wired so they: - CORRECT ANSWER ✔✔✔✔✔ Only operate
any time the EAC On-Off switch is turned to ON.
QUESTION : The LP gas manifold pressure is commonly what? - CORRECT
ANSWER ✔✔✔✔✔ 10 to 11 in. W.C.
QUESTION : The polarity of a 120V gas furnace equipped with electronic flame
rectification is important because: - CORRECT ANSWER ✔✔✔✔✔ The
ignition control may not prove flame.
2026 2027 GRADED A+
,3|Page
QUESTION : Using a voltmeter, a technician can determine voltage drop at a gas
furnace: - CORRECT ANSWER ✔✔✔✔✔ With the furnace not operating
and then with the furnace operating.
QUESTION : The setting on a 4 speed PSC blower motor can be changed by
changing the: - CORRECT ANSWER ✔✔✔✔✔ Motor tap connection.
QUESTION : When starting up a dual system, the temperature rise method for
determining airflow cannot be used with compressor cycle of the heat pump
because: - CORRECT ANSWER ✔✔✔✔✔ The capacity of the system
varies too much with outdoor temperature.
QUESTION : The flame pattern a technician would expect to see on a properly
operating single stage gas furnace equipped with "in shot" type burner is a: -
CORRECT ANSWER ✔✔✔✔✔ Hard and forceful flame with a light blue
appearance and little or no yellow.
QUESTION : What is recommended method for a pressurization leak test of a
fuel gas pipe? - CORRECT ANSWER ✔✔✔✔✔ Compressed air
QUESTION : What is a diaphragm type differential pressure gauge used for? -
CORRECT ANSWER ✔✔✔✔✔ Measure air pressure.
QUESTION : The pressure reading on a manometer is expressed in: -
CORRECT ANSWER ✔✔✔✔✔ Inches of water.
2026 2027 GRADED A+
, 4|Page
QUESTION : A technician measures the return air temperature of a 100,000 BTU
output gas furnace to be 65°F and the supply side air temperature is 135°F.
Calculate the CFM. - CORRECT ANSWER ✔✔✔✔✔ The CFM would be
1323.
QUESTION : A dirty or clogged air filter in an operating gas furnace can cause
what? - CORRECT ANSWER ✔✔✔✔✔ Increase temperature rise.
QUESTION : What can bent vanes on a direct drive blower wheel in a gas
furnace cause? - CORRECT ANSWER ✔✔✔✔✔ Loss in airflow, excessive
blower motor wear, and increase noise.
QUESTION : A gas clothes dryer can interfere with the operation of a nearby
natural draft gas furnace with an atmospheric burner by: - CORRECT
ANSWER ✔✔✔✔✔ Stealing combustion air preventing complete fuel
burning.
QUESTION : During a preventive maintenance check of a gas furnace, what
should always be checked for on the ductwork? - CORRECT ANSWER
✔✔✔✔✔ Ductwork should always be checked for leaks and damage.
QUESTION : When performing a cycle check during a preventive maintenance
call, the technician should: - CORRECT ANSWER ✔✔✔✔✔ ~First check
with the owner of the equipment for their opinion of performance.
~The next step is to turn the unit off at the thermostat system switch. ~Next the
technician should set the FAN switch to ON and check that the blower is
running.
2026 2027 GRADED A+
