Whirlpool 89263, 6510374 Temperature and Pressure Relief Valve, Closed System/Thermal Expansion

Closed System/Thermal Expansion

Periodic discharge of the temperature and pressure relief valve may be due to thermal expansion in a closed water supply system. The water utility supply meter may contain a check valve, backflow preventer or water pressure reducing valve. This will create a closed water system. During

the heating cycle of the water heater, the water expands causing pressure inside the water heater to increase. This may cause the temperature and pressure relief valve to discharge small quantities of hot water. To prevent this, it is recommended that a diaphragm-type expansion tank (suitable for potable water) be installed on the cold water supply line. The expansion tank must have a minimum capacity of 1.5 U.S. gallons for every 50 gallons of stored water. Contact the local water supplier or plumbing inspector for information on other methods to control this situation.

IMPORTANT: Do not plug or remove the temperature and pressure relief valve.

Temperature and Pressure Relief Valve

WARNING

Explosion Hazard

If the temperature and pressure relief valve is dripping or leaking, have a qualified person replace it.

Examples of a qualified person include: licensed plumbers, authorized gas company personnel, and authorized service personnel.

Do not plug valve. Do not remove valve.

Failure to follow these instructions can result in death, or explosion.

Figure 15A
Temperature and Pressure
Relief Valve Installation		Optional location
		some models only
		Temperature and
		Pressure Relief Valve
		Discharge line 3/4” maximum
		Do not cap or plug
		6” Maximum
Drain Pan	Drain

For protection against excessive pressures and temperatures, a temperature and pressure relief valve must be installed in the opening marked “T & P RELIEF VALVE” (see Figure 15A). This valve must be design certified by

a nationally recognized testing laboratory that maintains periodic inspection of the production of listed equipment or materials as meeting the requirements for Relief Valves and Automatic Shut-off Devices for Hot Water Supply Systems, ANSI Z21.22. The function of the temperature and pressure relief valve is to discharge water in large quantities in the event of excessive temperature or pressure developing

in the water heater. The valve’s relief pressure must not exceed the working pressure of the water heater as stated on the data plate.

IMPORTANT: Only a new temperature and pressure relief valve should be used with your water heater. Do not use an old or existing valve as it may be damaged or not adequate for the working pressure of the new water heater. Do not place any valve between the relief valve and the tank.

The Temperature & Pressure Relief Valve:

•Must not be in contact with any electrical part.

•Must be connected to an adequate discharge line.

•Must not be rated higher than the working pressure shown on the data plate of the water heater.

The Discharge Line:

•Must not be smaller than the pipe size of the relief valve or have any reducing coupling installed in the discharge line.

•Must not be capped, blocked, plugged or contain any valve between the relief valve and the end of the dis- charge line.

•Must terminate a maximum of six inches above a floor drain or external to the building.

•Must be capable of withstanding 250°F (121°C) without distortion.

•Must be installed to allow complete drainage of both the valve and discharge line.

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