A gas furnace to be installed in a garage. The national standards requires that the burners and ignition must be located ____ above the floor: 18 inches A good description of how a bi-metal fan switch operates the blower motor on a gas furnace is: Temperature on/ Temperature off Redundant gas valves used on gas furnaces will dual gas shut off seat Burning one cubic foot of Liquefied Petroleum gas completely will produce approximately ____ BTUs. 2,000 - 2,500 LP gas has a specific gravity of ...? 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? to mix primary air and gas Furnace limit switches are wired in series with the: 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. 3 feet A technician determines that a natural gas furnace has a defective heat exchanger. The technician should: Inform the home owner and turn the gas off.