HVAC NATE Gas Heat Exam Prep (Latest 2024/ 2025
Update) 100% Correct Questions and Verified
Answers| Grade A
What precautions are required when mounting any gas furnace on a wood platform
in an attic? - ANSWERNone
The gas control valve may be damaged if exposed to an inlet pressure above: -
ANSWER14 in. W.C.
How many elbows and joints should a vent connector have: - ANSWERAs few as
possible to reduce resistance of flue gases
What conditions, if any may a technician route the exhaust of the furnace into the
exhaust vent of the water heater? - ANSWERUnder 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: - ANSWERBy 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: -
ANSWERSupported with a minimum strap width of 1/2"
Installing a gas furnace and not an air conditioner has what affect on the installation
of the supply ductwork: - ANSWERLeave adequate space should be allowed for
addition of a coil in the future when feasible
Leveling of a Mercury bulb is: - ANSWERCritical
Spray-type atomizing humidifiers are installed to: - ANSWERDischarge moisture into
the supply duct
Electronic air cleaners (EAC) installed in a gas furnace system should be wired so
they: - ANSWEROnly operate any time the EAC On-Off switch is turned to ON.
The LP gas manifold pressure is commonly: - ANSWER10 to 11 in. W.C.
The polarity of a 120V gas furnace equipped with electronic flame rectification is
important because: - ANSWERThe ignition control may not prove flame
Using a voltmeter, a technician can determine voltage drop at a gas furnace: -
ANSWERWith 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: -
ANSWERMotor 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: -
ANSWERThe 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: - ANSWERHard and
forceful flame with a light blue appearance and little to no yellow
Compressed air is recommended for a: - ANSWERPressurization leak test of fuel gas
pipe
Diaphragm type differential pressure gauge is used to: - ANSWERMeasure air
pressure
The pressure reading on a manometer is expressed in: - ANSWERInches of water
A technician measures the return air temperature of a 100,000 BTU output gas
furnace to be 65 degrees and the supply side air temperature is 135 degrees: -
ANSWERThe CFM would be 1323
A dirty or clogged air filter in an operating gas furnace can cause an: -
ANSWERIncrease temperature rise
Bent vanes on a direct drive blower wheel in a gas furnace can cause a: -
ANSWERLoss 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: - ANSWERStealing combustion air
preventing complete fuel burning
During a preventive maintenance check of a gas furnace: - ANSWERDuctwork should
always be checked for leaks and damage
When performing a cycle check during a preventive maintenance call, the technician
should: - ANSWERFirst, check with owner for equipment performance
Next, turn the unit off at the thermostat system switch
Next, set fan switch to ON and check that the blower is running
The measurements required to calculate the CFM of a gas furnace are: -
ANSWEREntering 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: - ANSWERCompare temperature differential to nameplate rating
Update) 100% Correct Questions and Verified
Answers| Grade A
What precautions are required when mounting any gas furnace on a wood platform
in an attic? - ANSWERNone
The gas control valve may be damaged if exposed to an inlet pressure above: -
ANSWER14 in. W.C.
How many elbows and joints should a vent connector have: - ANSWERAs few as
possible to reduce resistance of flue gases
What conditions, if any may a technician route the exhaust of the furnace into the
exhaust vent of the water heater? - ANSWERUnder 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: - ANSWERBy 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: -
ANSWERSupported with a minimum strap width of 1/2"
Installing a gas furnace and not an air conditioner has what affect on the installation
of the supply ductwork: - ANSWERLeave adequate space should be allowed for
addition of a coil in the future when feasible
Leveling of a Mercury bulb is: - ANSWERCritical
Spray-type atomizing humidifiers are installed to: - ANSWERDischarge moisture into
the supply duct
Electronic air cleaners (EAC) installed in a gas furnace system should be wired so
they: - ANSWEROnly operate any time the EAC On-Off switch is turned to ON.
The LP gas manifold pressure is commonly: - ANSWER10 to 11 in. W.C.
The polarity of a 120V gas furnace equipped with electronic flame rectification is
important because: - ANSWERThe ignition control may not prove flame
Using a voltmeter, a technician can determine voltage drop at a gas furnace: -
ANSWERWith 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: -
ANSWERMotor 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: -
ANSWERThe 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: - ANSWERHard and
forceful flame with a light blue appearance and little to no yellow
Compressed air is recommended for a: - ANSWERPressurization leak test of fuel gas
pipe
Diaphragm type differential pressure gauge is used to: - ANSWERMeasure air
pressure
The pressure reading on a manometer is expressed in: - ANSWERInches of water
A technician measures the return air temperature of a 100,000 BTU output gas
furnace to be 65 degrees and the supply side air temperature is 135 degrees: -
ANSWERThe CFM would be 1323
A dirty or clogged air filter in an operating gas furnace can cause an: -
ANSWERIncrease temperature rise
Bent vanes on a direct drive blower wheel in a gas furnace can cause a: -
ANSWERLoss 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: - ANSWERStealing combustion air
preventing complete fuel burning
During a preventive maintenance check of a gas furnace: - ANSWERDuctwork should
always be checked for leaks and damage
When performing a cycle check during a preventive maintenance call, the technician
should: - ANSWERFirst, check with owner for equipment performance
Next, turn the unit off at the thermostat system switch
Next, set fan switch to ON and check that the blower is running
The measurements required to calculate the CFM of a gas furnace are: -
ANSWEREntering 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: - ANSWERCompare temperature differential to nameplate rating
