NATE Gas Heat Practice Guide
Questions with Guaranteed Pass
Solutions 2025-2026 Edition.
What precautions are required when mounting any gas furnace on a wood platform in an attic?
- Answer None
The gas control valve may be damaged if exposed to an inlet pressure above what? - Answer
14 inch W.C.
How many elbows and joints should a vent connector have? - Answer As few as possible to
reduce resistance of flue gases.
Under what conditions, if any may the technician route the exhaust of the furnace into the
exhaust vent of the water heater: - Answer Under no conditions may you use the water
heater exhaust vent.
How may a technician terminate the intake and exhaust for proper operation of a high efficiency
gas furnace when using scheduled 40 PVC pipe: - Answer By using the specific manufacturers
termination kit or make one to meet their requirements.
When suspended with metal strap and no saddle, flexible duct should be: - Answer
supported with a minimum strap width of
1/2".
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: - Answer Leave adequate space should be allowed for addition of a coil in the
future when feasible.
Leveling of a Mercury bulb is __________ - Answer Critical
Spray-type atomizing humidifiers are installed to do what? - Answer Discharge moisture into
the supply duct.
, The polarity of a 120V gas furnace equipped with electronic flame rectification is important
because: - Answer The ignition control may not prove flame.
Using a voltmeter, a technician can determine voltage drop at a gas furnace: - Answer With
the furnace not operating and then with the furnace operating.
The setting on a 4 speed PSC blower motor can be changed by changing the: - Answer Motor
tap connection.
When starting up a dual system, the temperature rise method for determining airflow cannot be
used with compressor cycle of the heat pump because: - Answer The capacity of the system
varies too much with outdoor temperature.
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: - Answer Hard and forceful flame with a
light blue appearance and little or no yellow.
What is recommended method for a pressurization leak test of a fuel gas pipe? - Answer
Compressed air
What is a diaphragm type differential pressure gauge used for? - Answer Measure air
pressure.
The pressure reading on a manometer is expressed in: - Answer Inches of water.
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. - Answer The CFM
would be 1323.
A dirty or clogged air filter in an operating gas furnace can cause what? - Answer Increase
temperature rise.
What can bent vanes on a direct drive blower wheel in a gas furnace cause? - Answer Loss in
airflow, excessive blower motor wear, and increase noise.
Questions with Guaranteed Pass
Solutions 2025-2026 Edition.
What precautions are required when mounting any gas furnace on a wood platform in an attic?
- Answer None
The gas control valve may be damaged if exposed to an inlet pressure above what? - Answer
14 inch W.C.
How many elbows and joints should a vent connector have? - Answer As few as possible to
reduce resistance of flue gases.
Under what conditions, if any may the technician route the exhaust of the furnace into the
exhaust vent of the water heater: - Answer Under no conditions may you use the water
heater exhaust vent.
How may a technician terminate the intake and exhaust for proper operation of a high efficiency
gas furnace when using scheduled 40 PVC pipe: - Answer By using the specific manufacturers
termination kit or make one to meet their requirements.
When suspended with metal strap and no saddle, flexible duct should be: - Answer
supported with a minimum strap width of
1/2".
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: - Answer Leave adequate space should be allowed for addition of a coil in the
future when feasible.
Leveling of a Mercury bulb is __________ - Answer Critical
Spray-type atomizing humidifiers are installed to do what? - Answer Discharge moisture into
the supply duct.
, The polarity of a 120V gas furnace equipped with electronic flame rectification is important
because: - Answer The ignition control may not prove flame.
Using a voltmeter, a technician can determine voltage drop at a gas furnace: - Answer With
the furnace not operating and then with the furnace operating.
The setting on a 4 speed PSC blower motor can be changed by changing the: - Answer Motor
tap connection.
When starting up a dual system, the temperature rise method for determining airflow cannot be
used with compressor cycle of the heat pump because: - Answer The capacity of the system
varies too much with outdoor temperature.
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: - Answer Hard and forceful flame with a
light blue appearance and little or no yellow.
What is recommended method for a pressurization leak test of a fuel gas pipe? - Answer
Compressed air
What is a diaphragm type differential pressure gauge used for? - Answer Measure air
pressure.
The pressure reading on a manometer is expressed in: - Answer Inches of water.
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. - Answer The CFM
would be 1323.
A dirty or clogged air filter in an operating gas furnace can cause what? - Answer Increase
temperature rise.
What can bent vanes on a direct drive blower wheel in a gas furnace cause? - Answer Loss in
airflow, excessive blower motor wear, and increase noise.
