NATE Gas Heat Practice Guide Exam Questions and Answers
|Fall 2025/2026 Update | 100% Correct Latest
Question 1
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.
Question 2
The blower access door is removed from a powered up gas furnace with a door interlock switch. Assume the switch has not
been modified, the technician read across the door interlock switch terminals should get:
Correct Answer
Volts
Question 3
According to mechanical codes, the unobstructed working space should be provided along the entire front (or firebox side)
of a warm-air gas furnace installed in an attic is:
Correct Answer
Not less than 30" in depth
Page 1 of 45
,Question 4
. When performing planned maintenance on a gas furnace check the wiring to be certain that:
Correct Answer
No wires have been broken or become loose.
Question 5
The maximum acceptable supply voltage tolerance for a 120 V circuit is:
Correct Answer
+/- 10%.
Question 6
The outdoor winter temperature for a gas furnace is called the:
Correct Answer
Outdoor design temperature.
Question 7
"Carry over" channels or "cross overs" are used to:
Correct Answer
Carry the flame from the first burner that lights to the remaining burners
Page 2 of 45
,Question 8
What an cause a lifting flame when igniting gas?
Correct Answer
Gas velocity is faster than burning speed
Question 9
A system that is oversized for the load:
Correct Answer
Will cause the unit to short cycle.
Question 10
The following conditions exist in a circuit that supplies power to three parallel loads.
Correct Answer
The total current in the circuit when operating will be the sum of the currents through each load.
Question 11
A system airflow check determines that supply static is 0.15 in. W.C. and return static is a negative 0.55 in. W.C. these
readings tell the technician:
Correct Answer
The difference between supply static and return static is unacceptably low.
Page 3 of 45
, Question 12
For indoor air quality purpose, economizers or fresh air supplies should:
Correct Answer
Never be located near a sewage vent
Question 13
A"cross break" made on all sides of any rectangular section of metal duct will:
Correct Answer
Increase rigidity and reduced vibration.
Question 14
Modern high-efficiency burners use combustion blowers. What are the two major types of combustion blowers?
Correct Answer
Induced draft and forced draft
Question 15
Undersizing a vent creates __________ and loads along __________
Correct Answer
Restriction, Induced draft motor
Page 4 of 45
|Fall 2025/2026 Update | 100% Correct Latest
Question 1
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.
Question 2
The blower access door is removed from a powered up gas furnace with a door interlock switch. Assume the switch has not
been modified, the technician read across the door interlock switch terminals should get:
Correct Answer
Volts
Question 3
According to mechanical codes, the unobstructed working space should be provided along the entire front (or firebox side)
of a warm-air gas furnace installed in an attic is:
Correct Answer
Not less than 30" in depth
Page 1 of 45
,Question 4
. When performing planned maintenance on a gas furnace check the wiring to be certain that:
Correct Answer
No wires have been broken or become loose.
Question 5
The maximum acceptable supply voltage tolerance for a 120 V circuit is:
Correct Answer
+/- 10%.
Question 6
The outdoor winter temperature for a gas furnace is called the:
Correct Answer
Outdoor design temperature.
Question 7
"Carry over" channels or "cross overs" are used to:
Correct Answer
Carry the flame from the first burner that lights to the remaining burners
Page 2 of 45
,Question 8
What an cause a lifting flame when igniting gas?
Correct Answer
Gas velocity is faster than burning speed
Question 9
A system that is oversized for the load:
Correct Answer
Will cause the unit to short cycle.
Question 10
The following conditions exist in a circuit that supplies power to three parallel loads.
Correct Answer
The total current in the circuit when operating will be the sum of the currents through each load.
Question 11
A system airflow check determines that supply static is 0.15 in. W.C. and return static is a negative 0.55 in. W.C. these
readings tell the technician:
Correct Answer
The difference between supply static and return static is unacceptably low.
Page 3 of 45
, Question 12
For indoor air quality purpose, economizers or fresh air supplies should:
Correct Answer
Never be located near a sewage vent
Question 13
A"cross break" made on all sides of any rectangular section of metal duct will:
Correct Answer
Increase rigidity and reduced vibration.
Question 14
Modern high-efficiency burners use combustion blowers. What are the two major types of combustion blowers?
Correct Answer
Induced draft and forced draft
Question 15
Undersizing a vent creates __________ and loads along __________
Correct Answer
Restriction, Induced draft motor
Page 4 of 45
