NATE GAS EXAM PREP VERSION 2 2026/2027
WITH ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS
|CURRENTLY TESTING QUESTIONS AND
SOLUTIONS|NEWEST |JUST
RELEASED!!|BRAND NEW VERSION
A combination fan-stat and high limit:
A: Are both safety controls
B: Consists of a high temperature safety thermostat built into the wall thermostat
C: Separate switches from a single helical bimetal, one switch controls the indoor fan, the other
acting as safety control
D: All the above are correct
C: Separate switches from a single helical bimetal, one switch controls the indoor fan, the other
acting as safety control
The three basic categories of ignition systems are:
A: Continuous ignition, intermittent ignition and direct ignition
B: Continuous ignition, direct ignition and manual ignition
C: Automatic ignition, intermittent ignition and direct ignition
D: Automatic ignition, direct ignition and indirect ignition
A: Continuous ignition, intermittent ignition and direct ignition
The intermittent ignition system:
A: Lights the burner directly
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,B: Uses a thermocouple
C: Lights the pilot only on a call for heat
D: Is the most efficient ignition system
C: Lights the pilot only on a call for heat
Direct ignition:
A: Uses a spark or hot surface igniter to light the burner directly
B: Gets its name from the fact that it is immediate, direct or fast acting
C: Lights the pilot only on a call for ignition
D: Is the most efficient ignition system
A: Uses a spark or hot surface igniter to light the burner directly
The flame sensor:
A: Is a thick ceramic rod that senses the heat of the flame and causes the rod to expand and
signal the solid state flame board that a flame is present
B: Is a small-diameter conducting rod that senses when a flame is present because a current
flow moves between the rod and the burner when the flame creates an electrical path between
them
C: Is actually a metal-oxide diode that rectifies alternating current to direct current for the gas
valve
D: Is a device that shuts down the main gas valve if the burner flame gets out of control and
starts burning outside the fire box or combustion chamber
B: Is a small-diameter conducting rod that senses when a flame is present because a current
flow moves between the rod and the burner when the flame creates an electrical path between
them
Which of the following is a typical sequence of operation for a high efficiency condensing
furnace?
A: induced draft blower runs for 20 seconds, ignitor heats for 15 seconds, gas valve opens,
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, burner lights off, flame sensor monitors the flame for the entire heating cycle until the
thermostat is satisfied
B: ignitor heats up for 15 seconds, gas valve opens and induced draft blower starts, burner lights
and then flame sensor takes over monitoring until the thermostat is satisfied
C: induced draft blower runs for 20 seconds, ignitor heats up for 15 seconds, gas valve opens,
burner lights off and flame sensor monitors flame. Plenum heats up, blower pulls air over the
heat exchanger
D: None of these is correct, as condensing furnaces do not use induced draft blowers.
C: induced draft blower runs for 20 seconds, ignitor heats up for 15 seconds, gas valve opens,
burner lights off and flame sensor monitors flame. Plenum heats up, blower pulls air over the
heat exchanger
A yellow burner flame is usually caused by:
A: A weak ignitor
B: Lack of sufficient air
C: Low gas pressure
D: Too much primary air
B: Lack of sufficient air
A lifting burner flame is usually caused by:
A: A new ignitor that has not been broken in
B: High gas pressure and/or too much primary air
C: Low gas pressure and/or not enough primary air
D: Blockage in the flue
B: High gas pressure and/or too much primary air
What is the purpose of "timing a gas meter"?
A: To determine the actual input in Btuh of the furnace
3|Page
WITH ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS
|CURRENTLY TESTING QUESTIONS AND
SOLUTIONS|NEWEST |JUST
RELEASED!!|BRAND NEW VERSION
A combination fan-stat and high limit:
A: Are both safety controls
B: Consists of a high temperature safety thermostat built into the wall thermostat
C: Separate switches from a single helical bimetal, one switch controls the indoor fan, the other
acting as safety control
D: All the above are correct
C: Separate switches from a single helical bimetal, one switch controls the indoor fan, the other
acting as safety control
The three basic categories of ignition systems are:
A: Continuous ignition, intermittent ignition and direct ignition
B: Continuous ignition, direct ignition and manual ignition
C: Automatic ignition, intermittent ignition and direct ignition
D: Automatic ignition, direct ignition and indirect ignition
A: Continuous ignition, intermittent ignition and direct ignition
The intermittent ignition system:
A: Lights the burner directly
1|Page
,B: Uses a thermocouple
C: Lights the pilot only on a call for heat
D: Is the most efficient ignition system
C: Lights the pilot only on a call for heat
Direct ignition:
A: Uses a spark or hot surface igniter to light the burner directly
B: Gets its name from the fact that it is immediate, direct or fast acting
C: Lights the pilot only on a call for ignition
D: Is the most efficient ignition system
A: Uses a spark or hot surface igniter to light the burner directly
The flame sensor:
A: Is a thick ceramic rod that senses the heat of the flame and causes the rod to expand and
signal the solid state flame board that a flame is present
B: Is a small-diameter conducting rod that senses when a flame is present because a current
flow moves between the rod and the burner when the flame creates an electrical path between
them
C: Is actually a metal-oxide diode that rectifies alternating current to direct current for the gas
valve
D: Is a device that shuts down the main gas valve if the burner flame gets out of control and
starts burning outside the fire box or combustion chamber
B: Is a small-diameter conducting rod that senses when a flame is present because a current
flow moves between the rod and the burner when the flame creates an electrical path between
them
Which of the following is a typical sequence of operation for a high efficiency condensing
furnace?
A: induced draft blower runs for 20 seconds, ignitor heats for 15 seconds, gas valve opens,
2|Page
, burner lights off, flame sensor monitors the flame for the entire heating cycle until the
thermostat is satisfied
B: ignitor heats up for 15 seconds, gas valve opens and induced draft blower starts, burner lights
and then flame sensor takes over monitoring until the thermostat is satisfied
C: induced draft blower runs for 20 seconds, ignitor heats up for 15 seconds, gas valve opens,
burner lights off and flame sensor monitors flame. Plenum heats up, blower pulls air over the
heat exchanger
D: None of these is correct, as condensing furnaces do not use induced draft blowers.
C: induced draft blower runs for 20 seconds, ignitor heats up for 15 seconds, gas valve opens,
burner lights off and flame sensor monitors flame. Plenum heats up, blower pulls air over the
heat exchanger
A yellow burner flame is usually caused by:
A: A weak ignitor
B: Lack of sufficient air
C: Low gas pressure
D: Too much primary air
B: Lack of sufficient air
A lifting burner flame is usually caused by:
A: A new ignitor that has not been broken in
B: High gas pressure and/or too much primary air
C: Low gas pressure and/or not enough primary air
D: Blockage in the flue
B: High gas pressure and/or too much primary air
What is the purpose of "timing a gas meter"?
A: To determine the actual input in Btuh of the furnace
3|Page
