NATE Gas questions with Correct
Answers
What is the typical load rating of the branch circuit over-current protection for a residential gas
furnace? - ANSWER✔✔-15 Amp
When selecting a replacement indoor blower motor, which criteria should be included? -
ANSWER✔✔-Motor horsepower
What is the primary purpose of an off-delay timer in a gas furnace? - ANSWER✔✔-Remove
residual hear and prevent nuisance limit trips
To minimize noise problems in residential duct systems, what is the range (recommended to
maximum) of design air velocity in the rectangular main supply trunk? - ANSWER✔✔-700 to 900
fpm
What is recommended for a pressurization leak test of fuel gas pipe? - ANSWER✔✔-Compressed
air
Induced draft blowers in direct vent condensing furnaces pull combustion air from - ANSWER✔✔-
outdoors only
FOR STUDY PURPOSES ONLY COPYRIGHT © 2025 ALL RIGHTS RESERVED 1
, Combustion air is often brought into a non-direct vent gas furnace, located in an interior closet
(confined space). What consideration is important to remember? - ANSWER✔✔-Two permanent
openings of sufficient size must be used
The height limitation for a vertical combustion air intake on a condensing gas furnace is set by -
ANSWER✔✔-the furnace manufacturer
When working on burners in a gas function - ANSWER✔✔-the individual burners must be
mounted in correct alignment
A thermopile system usually generates its own control circuit voltage of - ANSWER✔✔-750 mV
There are two generally used methods for controlling temperature and humidity within individual
zones of a residence. One is to use dampers to control supply airflow to each zone. What is the
other method? - ANSWER✔✔-Use separate and independent systems to condition the air in each
zone
The complaint is that there is static electricity throughout the house. The home has a bypass
humidifier. The technician has checked the humidistat and verified that it is set properly.
What would the technician check next? - ANSWER✔✔-Check that the humidifier damper is open
A line voltage fuse is sized to - ANSWER✔✔-protect from excessive voltage
14. With a non-direct vented furnace located in a basement, what are the requirements for the space
to qualify as an "unconfined space"? - ANSWER✔✔-At least 50 ft of air volume for every
1000 Btu/h capacity of ail combustion appliances in the space
FOR STUDY PURPOSES ONLY COPYRIGHT © 2025 ALL RIGHTS RESERVED 2
Answers
What is the typical load rating of the branch circuit over-current protection for a residential gas
furnace? - ANSWER✔✔-15 Amp
When selecting a replacement indoor blower motor, which criteria should be included? -
ANSWER✔✔-Motor horsepower
What is the primary purpose of an off-delay timer in a gas furnace? - ANSWER✔✔-Remove
residual hear and prevent nuisance limit trips
To minimize noise problems in residential duct systems, what is the range (recommended to
maximum) of design air velocity in the rectangular main supply trunk? - ANSWER✔✔-700 to 900
fpm
What is recommended for a pressurization leak test of fuel gas pipe? - ANSWER✔✔-Compressed
air
Induced draft blowers in direct vent condensing furnaces pull combustion air from - ANSWER✔✔-
outdoors only
FOR STUDY PURPOSES ONLY COPYRIGHT © 2025 ALL RIGHTS RESERVED 1
, Combustion air is often brought into a non-direct vent gas furnace, located in an interior closet
(confined space). What consideration is important to remember? - ANSWER✔✔-Two permanent
openings of sufficient size must be used
The height limitation for a vertical combustion air intake on a condensing gas furnace is set by -
ANSWER✔✔-the furnace manufacturer
When working on burners in a gas function - ANSWER✔✔-the individual burners must be
mounted in correct alignment
A thermopile system usually generates its own control circuit voltage of - ANSWER✔✔-750 mV
There are two generally used methods for controlling temperature and humidity within individual
zones of a residence. One is to use dampers to control supply airflow to each zone. What is the
other method? - ANSWER✔✔-Use separate and independent systems to condition the air in each
zone
The complaint is that there is static electricity throughout the house. The home has a bypass
humidifier. The technician has checked the humidistat and verified that it is set properly.
What would the technician check next? - ANSWER✔✔-Check that the humidifier damper is open
A line voltage fuse is sized to - ANSWER✔✔-protect from excessive voltage
14. With a non-direct vented furnace located in a basement, what are the requirements for the space
to qualify as an "unconfined space"? - ANSWER✔✔-At least 50 ft of air volume for every
1000 Btu/h capacity of ail combustion appliances in the space
FOR STUDY PURPOSES ONLY COPYRIGHT © 2025 ALL RIGHTS RESERVED 2
