Gas Heat esco exam Questions and
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A gas furnace to be installed in a garage. The national standards
requires that the burners and ignition must be located ____ above
the floor:
Ans: 18 inches
A good description of how a bi-metal fan switch operates the
blower motor on a gas furnace is:
Ans: Temperature on/ Temperature off
Redundant gas valves used on gas furnaces will shut down if gas
pressure exceeds:
Ans: 13.5 in W.C. (or 1/2 psi)
This is the maximum pressure for gas valve operation
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Burning one cubic foot of Liquefied Petroleum gas completely will
produce approximately ____ BTUs.
Ans: 2,000 - 2,500
LP gas has a specific gravity of ...?
Ans: 1.5 - 2.0 ( actual is 1.5 heavier than air which is 1.0)
What is the purpose of a spoiler screw located on a burner, or
adjustable-shutters?
Ans: to mix primary air and gas
Furnace limit switches are wired in series with the:
Ans: Gas valve
A technician is using an extension ladder to work on roof top unit.
The top of the ladder should extend _____ beyond the support point.
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Ans: 3 feet
A technician determines that a natural gas furnace has a defective
heat exchanger. The technician should:
Ans: Inform the home owner and turn the gas off.
A natural gas furnace usually requires _____ gas pressure AT the
manifold and burners.
What should the inlet pressure be to the manifold?
Ans: 3.5 in WC
inlet- 5-7 in WC
The vent system for a condensing furnace is classified as ___ by the
National Field Gas Code.
Ans: Category IV (4)