Desa GWP20T GWN30T, WMP20, GP30 GN30T Connecting to GAS Supply, Typical Inlet Pipe Diameters

INSTALLATION

Connecting To Gas Supply

11

INSTALLATION

Continued

CONNECTING TO GAS SUPPLY

WARNING: This appliance requires a 3/8" NPT (National Pipe Thread) inlet connection to the pres- sure regulator.

WARNING: A qualified service person must con- nect heater to gas supply. Follow all local codes.

WARNING: For natural gas, never connect heater to private (non-utility) gas wells. This gas is com- monly known as wellhead gas.

IMPORTANT: For natural gas, check gas line pressure before connecting heater to gas line. Gas line pressure must be no greater than 14 inches of water. If gas line pressure is higher, heater regulator damage could occur.

Typical Inlet Pipe Diameters

20,000 Btu/Hr Models - 3/8" or greater

30,000 Btu/Hr Models - 1/2" or greater

Installation must include equipment shutoff valve, union, and plugged 1/8" NPT tap. Locate NPT tap within reach for test gauge hook up. NPT tap must be upstream from heater (see Figure 15).

IMPORTANT: Install an equipment shutoff valve in an accessible location. The equipment shutoff valve is for turning on or shutting off the gas to the appliance.

Apply pipe joint sealant lightly to male NPT threads. This will prevent excess sealant from going into pipe. Excess sealant in pipe could result in clogged heater valves.

WARNING: Use pipe joint sealant that is resistant to liquid petroleum (LP) gas.

CAUTION: For propane/LP gas, never connect heater directly to the propane/LP supply. This heater requires an external regulator (not supplied). Install the external regulator between the heater and pro- pane/LP supply.

For propane/LP gas, the installer must supply an external regulator. The external regulator will reduce incoming gas pressure. You must reduce incoming gas pressure to between 11 and 14 inches of water. If you do not reduce incoming gas pressure, heater regulator damage could occur. Install the external regulator with the vent pointing down as shown in Figure 14. Pointing the vent down protects it from freezing rain or sleet.

Install sediment trap in supply line as shown in Figure 15. Locate sediment trap where it is within reach for cleaning. Locate sediment trap where trapped matter is not likely to freeze. A sediment trap traps moisture and contaminants. This keeps them from going into heater controls. If sediment trap is not installed or is installed wrong, heater may not run properly.

IMPORTANT: Hold the pressure regulator with wrench when connecting it to gas piping and/or fittings. Do not over tighten pipe connection to regulator. The regulator body could be damaged.

Pressure	Note: Burner
	bracket not
Regulator	shown for
	clarity

Propane/LP

Supply

Tank

External

Regulator

Vent

Pointing

Down

	3/8" NPT
	Pipe Nipple	Heater
	Tee Joint	Cabinet
		Ground Joint Union
Test	Reducer
		Equipment
Gauge	Bushing to
Con-	1/8" NPT	Shutoff Valve *
nection*	1/8" NPT	Natural Gas
	Plug Tap	From Gas Meter
	Tee	(5" W.C. to 10.5" W.C.
	Joint	Pressure)

Figure 14 - External Regulator With Vent Pointing Down

CAUTION: Use only new, black iron or steel pipe. Internally-tinned copper tubing may be used in cer- tain areas. Check your local codes. Use pipe of large enough diameter to allow proper gas volume to heater. If pipe is too small, undue loss of volume will occur.

Sediment	Pipe	3"	Propane/LP
Trap	Nipple	Minimum	From External
	Cap		Regulator
			(11" W.C. to 14" W.C.
Figure 15 - Gas Connection
			Pressure)

*A CSA design-certified equipment shutoff valve with 1/8" NPT tap is an acceptable alternative to test gauge connection. Purchase the optional CSA design-certified equipment shutoff valve from your dealer. See Accessories, page 27.

For more information, visit www.desatech.com

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