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Suspended type unit heaters shall have a clearance from combustible materials of at least 18 inches at the sides and 12 inches at the bottom. How much clearance is required at the top if it has a vertical draft hood installed?

The coil of the potential starting relay is connected in parallel with:

Identify the following motor wiring diagram:

Size section #2 in the drawing above using the longest length method and the pipe sizing tables in the International Fuel Gas Code. The natural gas supplied has a 0.60 specific gravity and a heating value of 1000 Btu per cubic foot with a designated pressure drop of 0.5 inches W.C. The material is schedule 40 black iron pipe.

Liquidtight flexible non-metal conduit shall be securely fastened and supported:

Truss members shall not be cut, drilled, spliced or notched or altered without the written approval of a registered design professional.

When the water and refrigerant in a heat exchanger flow in opposite directions, it is referred to as ____.

Permits for HVAC installation or modification must be obtained prior to work starting.

Excess air for combustion appliances consists of:

Floor furnaces shall not be closer than 6 inches to the nearest wall and not less than _____ inches from the two adjoining sides