NATE Gas Heat Practice Guide with
correct answers 2026
What-precautions-are-required-when-mounting-any-gas-furnace-on-a-wood-platform-in-an-
attic?---correct-answers--None
The-gas-control-valve-may-be-damaged-if-exposed-to-an-inlet-pressure-above-what?---correct-
answers--14-inch-W.C.
How-many-elbows-and-joints-should-a-vent-connector-have?---correct-answers--As-few-as-
possible-to-reduce-resistance-of-flue-gases.
Under-what-conditions,-if-any-may-the-technician-route-the-exhaust-of-the-furnace-into-the-
exhaust-vent-of-the-water-heater:---correct-answers--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-answers--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-answers--
supported-with-a-minimum-strap-width-of
1/2".
,A-technician-is-installing-a-gas-furnace-and-the-customer-has-decided-not-to-install-an-air-
conditioner.-Making-this-decision,-the-affect-it-will-have-on-the-installation-of-the-supply-
ductwork-is:---correct-answers--Leave-adequate-space-should-be-allowed-for-addition-of-a-coil-
in-the-future-when-feasible.
Leveling-of-a-Mercury-bulb-is-__________---correct-answers--Critical
Spray-type-atomizing-humidifiers-are-installed-to-do-what?---correct-answers--Discharge-
moisture-into-the-supply-duct.
Electronic-air-cleaners-(EAC)-installed-in-a-gas-furnace-system-should-be-wired-so-they:---
correct-answers--Only-operate-any-time-the-EAC-On-Off-switch-is-turned-to-ON.
The-LP-gas-manifold-pressure-is-commonly-what?---correct-answers--10-to-11-in.-W.C.
The-polarity-of-a-120V-gas-furnace-equipped-with-electronic-flame-rectification-is-important-
because:---correct-answers--The-ignition-control-may-not-prove-flame.
Using-a-voltmeter,-a-technician-can-determine-voltage-drop-at-a-gas-furnace:---correct-
answers--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-
answers--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-answers--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-answers--Hard-and-forceful-flame-
with-a-light-blue-appearance-and-little-or-no-yellow.
What-is-recommended-method-for-a-pressurization-leak-test-of-a-fuel-gas-pipe?---correct-
answers--Compressed-air
What-is-a-diaphragm-type-differential-pressure-gauge-used-for?---correct-answers--Measure-
air-pressure.
The-pressure-reading-on-a-manometer-is-expressed-in:---correct-answers--Inches-of-water.
A-technician-measures-the-return-air-temperature-of-a-100,000-BTU-output-gas-furnace-to-be-
65°F-and-the-supply-side-air-temperature-is-135°F.-Calculate-the-CFM.---correct-answers--The-
CFM-would-be-1323.
A-dirty-or-clogged-air-filter-in-an-operating-gas-furnace-can-cause-what?---correct-answers--
Increase-temperature-rise.
What-can-bent-vanes-on-a-direct-drive-blower-wheel-in-a-gas-furnace-cause?---correct-
answers--Loss-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:---correct-answers--Stealing-combustion-air-preventing-
complete-fuel-burning.
During-a-preventive-maintenance-check-of-a-gas-furnace,-what-should-always-be-checked-for-
on-the-ductwork?---correct-answers--Ductwork-should-always-be-checked-for-leaks-and-
damage.
correct answers 2026
What-precautions-are-required-when-mounting-any-gas-furnace-on-a-wood-platform-in-an-
attic?---correct-answers--None
The-gas-control-valve-may-be-damaged-if-exposed-to-an-inlet-pressure-above-what?---correct-
answers--14-inch-W.C.
How-many-elbows-and-joints-should-a-vent-connector-have?---correct-answers--As-few-as-
possible-to-reduce-resistance-of-flue-gases.
Under-what-conditions,-if-any-may-the-technician-route-the-exhaust-of-the-furnace-into-the-
exhaust-vent-of-the-water-heater:---correct-answers--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-answers--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-answers--
supported-with-a-minimum-strap-width-of
1/2".
,A-technician-is-installing-a-gas-furnace-and-the-customer-has-decided-not-to-install-an-air-
conditioner.-Making-this-decision,-the-affect-it-will-have-on-the-installation-of-the-supply-
ductwork-is:---correct-answers--Leave-adequate-space-should-be-allowed-for-addition-of-a-coil-
in-the-future-when-feasible.
Leveling-of-a-Mercury-bulb-is-__________---correct-answers--Critical
Spray-type-atomizing-humidifiers-are-installed-to-do-what?---correct-answers--Discharge-
moisture-into-the-supply-duct.
Electronic-air-cleaners-(EAC)-installed-in-a-gas-furnace-system-should-be-wired-so-they:---
correct-answers--Only-operate-any-time-the-EAC-On-Off-switch-is-turned-to-ON.
The-LP-gas-manifold-pressure-is-commonly-what?---correct-answers--10-to-11-in.-W.C.
The-polarity-of-a-120V-gas-furnace-equipped-with-electronic-flame-rectification-is-important-
because:---correct-answers--The-ignition-control-may-not-prove-flame.
Using-a-voltmeter,-a-technician-can-determine-voltage-drop-at-a-gas-furnace:---correct-
answers--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-
answers--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-answers--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-answers--Hard-and-forceful-flame-
with-a-light-blue-appearance-and-little-or-no-yellow.
What-is-recommended-method-for-a-pressurization-leak-test-of-a-fuel-gas-pipe?---correct-
answers--Compressed-air
What-is-a-diaphragm-type-differential-pressure-gauge-used-for?---correct-answers--Measure-
air-pressure.
The-pressure-reading-on-a-manometer-is-expressed-in:---correct-answers--Inches-of-water.
A-technician-measures-the-return-air-temperature-of-a-100,000-BTU-output-gas-furnace-to-be-
65°F-and-the-supply-side-air-temperature-is-135°F.-Calculate-the-CFM.---correct-answers--The-
CFM-would-be-1323.
A-dirty-or-clogged-air-filter-in-an-operating-gas-furnace-can-cause-what?---correct-answers--
Increase-temperature-rise.
What-can-bent-vanes-on-a-direct-drive-blower-wheel-in-a-gas-furnace-cause?---correct-
answers--Loss-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:---correct-answers--Stealing-combustion-air-preventing-
complete-fuel-burning.
During-a-preventive-maintenance-check-of-a-gas-furnace,-what-should-always-be-checked-for-
on-the-ductwork?---correct-answers--Ductwork-should-always-be-checked-for-leaks-and-
damage.
