Desa VMH3000TPA installation manual Connecting To Gas Supply, Installation, Continued

12

INSTALLATION

Connecting To Gas Supply

INSTALLATION

Continued

CONNECTING TO GAS SUPPLY

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

Installation must include an 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 19).

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

Check your building codes for any special requirements for locating equipment shutoff valve to heater.

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

WARNING: Never connect natural gas heater to private (non-utility) gas wells. This gas is commonly known as wellhead gas.

CAUTION: Never connect propane/LP heater di- rectly to the propane/LP supply. This heater requires an external regulator (not supplied). Install the external regulator between the heater and propane/LP supply.

IMPORTANT: 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.

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.

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

We recommend that you install a sediment trap in supply line as shown in Figure 19, below. Locate sediment trap where it is within reach for cleaning. Install in piping system between fuel supply and heater. 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 pressure regulator with wrench when con- necting it to gas piping and/or fittings.

For propane/LP gas only, 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 external regulator with the vent pointing down as shown in Figure 18. Pointing the vent down protects it from freezing rain or sleet.

Pressure	Note: Burner bracket
	not shown for clarity
Regulator

3/8" NPT Pipe Nipple

Propane/LP			Ground		Heater
Supply Tank
					Cabinet
External			Union
		Tee Joint
Regulator
			Joint
Test
		Reducer
Gauge				Equipment Shutoff
		Bushing to
Connection *				Valve *
		1/8" NPT
				Natural Gas
Vent		1/8" NPT
				From Gas Meter
Pointing		Plug Tap		(5" W.C. to 10.5"
Down		Tee Joint		W.C. Pressure)
			3"	Propane/LP
	Sediment Pipe Nipple			From External
Figure 18 - External Regulator with Vent Pointing Down	Trap	Cap	Minimum	Regulator
				(11" W.C. to 14"
(Propane/LP Only)
				W.C. Pressure)
	Figure 19 - Gas Connection
CAUTION: Use only new, black iron or steel pipe.
	* A CSA design-certified equipment shutoff valve with 1/8" NPT
Internally-tinned copper tubing may be used in cer-
tain areas. Check your local codes. Use pipe of 1/2" or	tap is an acceptable alternative to test gauge connection. Purchase
greater diameter to allow proper gas volume to heater.	the optional CSA design-certified equipment shutoff valve from
If pipe is too small, undue loss of volume will occur.	your dealer. See Accessories, page 21.

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