NATE Gas Heat Practice Actual Exam
2026 Latest Update Questions and
Correct Answers Rated A+
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.
Electronic air cleaners (EAC) installed in a gas furnace system should
be wired so they: -Answer-Only operate any time the EAC On-Off
switch is turned to ON.
The LP gas manifold pressure is commonly what? -Answer-10 to 11
in. W.C.
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.
A gas clothes dryer can interfere with the operation of a nearby natural
draft gas furnace with an atmospheric burner by: -Answer-Stealing
combustion air preventing complete fuel burning.
During a preventive maintenance check of a gas furnace, what should
always be checked for on the ductwork? -Answer-Ductwork should
always be checked for leaks and damage.
, When performing a cycle check during a preventive maintenance call,
the technician should: -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.
What measurements are required to calculate the CFM of a gas
furnace are? -Answer-~Entering air temperature
~Leaving air temperature
~Outdoor ambient and rated capacity.
The reason for checking the temperature rise across the heat
exchanger of a gas furnace is to: -Answer-Compare temperature
differential to nameplate rating.
The technician is checking the operation of an induced draft furnace
with an atmospheric burner and a direct ignition system. On a call for
heat the sequence is what? -Answer-~Vent blower comes on
~Igniter glows
~Main burner does not light
~The next check would be the gas supply and/or gas valve
The technician is servicing a gas furnace located in a basement and
the complaint is "not enough heat". The following conditions exist: -
Answer-Properly sized furnace is operating correctly
Temperature rise is within specification
Filter is clean and CFM from blower is proper
2026 Latest Update Questions and
Correct Answers Rated A+
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.
Electronic air cleaners (EAC) installed in a gas furnace system should
be wired so they: -Answer-Only operate any time the EAC On-Off
switch is turned to ON.
The LP gas manifold pressure is commonly what? -Answer-10 to 11
in. W.C.
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.
A gas clothes dryer can interfere with the operation of a nearby natural
draft gas furnace with an atmospheric burner by: -Answer-Stealing
combustion air preventing complete fuel burning.
During a preventive maintenance check of a gas furnace, what should
always be checked for on the ductwork? -Answer-Ductwork should
always be checked for leaks and damage.
, When performing a cycle check during a preventive maintenance call,
the technician should: -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.
What measurements are required to calculate the CFM of a gas
furnace are? -Answer-~Entering air temperature
~Leaving air temperature
~Outdoor ambient and rated capacity.
The reason for checking the temperature rise across the heat
exchanger of a gas furnace is to: -Answer-Compare temperature
differential to nameplate rating.
The technician is checking the operation of an induced draft furnace
with an atmospheric burner and a direct ignition system. On a call for
heat the sequence is what? -Answer-~Vent blower comes on
~Igniter glows
~Main burner does not light
~The next check would be the gas supply and/or gas valve
The technician is servicing a gas furnace located in a basement and
the complaint is "not enough heat". The following conditions exist: -
Answer-Properly sized furnace is operating correctly
Temperature rise is within specification
Filter is clean and CFM from blower is proper
