NATE - Gas & Heat questions and answers 2026\2027
A+ Grade
What precautions are required when mounting any gas furnace on a wood platform in an attic?
- correct answer None
The gas control valve may be damaged if exposed to an inlet pressure above:
- correct answer 14 in. W.C.
How many elbows and joints should a vent connector have:
- correct answer As 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?
- correct 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:
- correct 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:
- correct answer Supported 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:
- correct answer Leave adequate space should be allowed for addition of a coil in the future when
feasible
Leveling of a Mercury bulb is:
- correct answer Critical
, Spray-type atomizing humidifiers are installed to:
- correct answer Discharge moisture into the supply duct
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.
The LP gas manifold pressure is commonly:
- correct answer 10 to 11 in. W.C.
The polarity of a 120V gas furnace equipped with electronic flame rectification is important because:
- correct answer The ignition control may not prove flame
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.
The setting on a 4 speed PSC blower motor can be changed by changing the:
- correct 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:
- correct 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:
- correct answer Hard and forceful flame with a light blue appearance and little to no yellow
Compressed air is recommended for a:
- correct answer Pressurization leak test of fuel gas pipe
Diaphragm type differential pressure gauge is used to:
- correct answer Measure air pressure
A+ Grade
What precautions are required when mounting any gas furnace on a wood platform in an attic?
- correct answer None
The gas control valve may be damaged if exposed to an inlet pressure above:
- correct answer 14 in. W.C.
How many elbows and joints should a vent connector have:
- correct answer As 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?
- correct 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:
- correct 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:
- correct answer Supported 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:
- correct answer Leave adequate space should be allowed for addition of a coil in the future when
feasible
Leveling of a Mercury bulb is:
- correct answer Critical
, Spray-type atomizing humidifiers are installed to:
- correct answer Discharge moisture into the supply duct
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.
The LP gas manifold pressure is commonly:
- correct answer 10 to 11 in. W.C.
The polarity of a 120V gas furnace equipped with electronic flame rectification is important because:
- correct answer The ignition control may not prove flame
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.
The setting on a 4 speed PSC blower motor can be changed by changing the:
- correct 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:
- correct 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:
- correct answer Hard and forceful flame with a light blue appearance and little to no yellow
Compressed air is recommended for a:
- correct answer Pressurization leak test of fuel gas pipe
Diaphragm type differential pressure gauge is used to:
- correct answer Measure air pressure
