White Rodgers 37C73U Installation, Removing OLD Control, Installing NEW Control

INSTALLATION

REPLACEMENT INFORMATION

REMOVING OLD CONTROL

1.	Turn off gas supply to the water heater at the manual gas
	shut-off valve. This valve is typically located beside the
	water heater.
2.	Locate the gas control valve/thermostat. Before performing
	any maintenance, turn the temperature dial on the gas
	control valve/thermostat to the lowest setting. (See To light
	Appliance Figure 2)
3.	On the top of the gas control valve turn the gas control
	knob to the “Off” position. (See To light Appliance Figure A)
	NOTE: On the White-Rodgers gas control valve/
	thermostat the knob stop must first be slightly
	depressed before turning the gas control knob.
4.	Close the cold water inlet valve to the water heater and
	open a nearby hot water faucet.
5.	Connect a hose to the drain valve and terminate it to an

Gas supply pipe

Gas shut-off

valve

Union

(metal-to-metal)

Tee

Drip leg

(sediment trap)

Pipe cap

		LI	PIL
				OT
		GHTI
				N
				G
Y		ER T OTH
R T
VEHO	RE ATWEEAS NCR		I	L
C	H TIW S	SOF KRIS
	G NI DLCA	C		O
B	:AUTION			W
	A

To pilot burner

To main burner

To thermocouple

	adequate drain. Open water heater drain valve by turning
	handle counterclockwise to drain water heater tank.
	IMPORTANT: DO NOT proceed to the following steps
	until the water heater is completely drained.
6.	On some water heaters, the outer door may need to be
	removed.
7.	If control doesn’t have a piezo ignitor, skip to step (8) or
	disconnect the piezo ignitor wire from the piezo ignitor
	button.
	NOTE: There are two types of ignitors. If you have the
	square ignitor, slide the ignitor bracket backward away
	from the gas valve to remove it. If you have a round
	ignitor, first remove the ignitor from the bracket by
	depressing front and rear holding tabs and lift. Next
	remove ignitor bracket from the gas valve. Keep ignitor
	and bracket.
8.	Disconnect the thermocouple, pilot tube, and manifold
	(burner) tube. Some control may have two wires (flying
	leads) attached to the thermal switch that must be
	disconnected as well.
9.	Disconnect the union joint in the gas piping. Disconnect the
	remaining pipe from the gas control valve/thermostat.
10.	Remove the control by turning it counterclockwise. If
	needed, a short piece of ½” black iron pipe can be screwed
	into the control inlet to increase leverage.

INSTALLING NEW CONTROL

All piping must comply with local and state ordinances or with the National Fuel Gas Code (ANSI Z223.1–NFPA 54), which- ever applies.

Dirt or contamination in the gas line can block the control from operating creating a risk of explosion, injury or death. To protect the control from dirt/contamination, a drip leg or sediment trap (see Figure 1) must be installed in the piping to the control.

1.To replace the gas control valve/thermostat, reassemble in reverse order. When replacing the gas valve, use a short piece of pipe to help turn control. (Clockwise) DO NOT OVER TIGHTEN or damage may result. Use an approved pipe compound on the threads that screw into the tank and to the gas pipe that screw into the gas control valve/thermostat. Do not use TEFLON tape. Do not apply compound to first two threads on gas pipe.

2.Reconnect the gas piping to the gas control valve/ thermostat. Use new black iron pipe that has been properly reamed. If old pipe is used, be sure it is clean and free from rust and scale.

FigureFigure1. Typical1. gasconnection

3.If control had an ignitor, transfer the ignitor and bracket removed from the old gas control valve to the new one.

4.Reconnect manifold tube (burner), pilot tube, ignitor wire (if present), flying leads (if present), Thermocouple nut (thermocouple nut should be hand tightened and then turned an additional ¼ turn with small wrench. DO NOT OVERTIGHTEN. Do not use pipe joint compound or TEFLON tape on manifold, pilot, and thermocouple connections.

5.Reconnect union. DO NOT use joint compound or TEFLON tape on union connection.

6.Close the water heater drain valve by turning the handle to the right (clockwise). Open the cold water supply valve to the water heater to fill the water heater tank.

NOTE: The cold water supply valve must be left open when the water heater is in use.

Keep the nearby hot water faucet open for 3 minutes after a constant flow of water is obtained to purge the lines of any excess air. Check all new water piping for leaks. Repair as needed.

!CAUTION

Never use this water heater unless it is completely filled with water. To prevent damage to the tank, the tank must be filled with water. Water must flow from the hot water faucet before turning ON gas to the water heater.

7.Turn on gas shutoff valve.

!WARNING

DO NOT USE OPEN FLAME OR ANY KIND OF SPARK TO CHECK FOR LEAKS. Serious injury of death from fire or explosion could result.

8.BEFORE LIGHTING THE PILOT, CHECK THE GAS LINES FOR LEAKS. Use a soapy water solution. DO NOT test for gas leaks using a match or open flame.

Brush the soapy water solution on all gas pipes, joints, and fittings. Check for bubbling soap indicating you have a leak. Turn OFF the gas and make the necessary repairs. Recheck for leaks. Rinse off soapy solution and wipe dry.

9.Affix the new Lighting instruction label on the water heater to cover the existing label.

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