Kenmore 153.336433 Closed System/Thermal Expansion, Temperature and Pressure Relief Valve

Closed System/Thermal Expansion

As water is heated, it expands (thermal expansion). In a closed system, the volume of water will grow. As the volume of water grows, there will be a corresponding increase in water pressure due to thermal expansion. Thermal expansion can cause premature tank failure (leakage). This type of failure is not covered under the limited warranty. Thermal expansion can also cause intermittent temperature-pressure relief valve operation: water discharged from the valve due to excessive pressure build up. The temperature-pressure relief valve is not intended for the constant relief of thermal expansion. This condition is not covered under the limited warranty.

A properly sized thermal expansion tank should be installed on all closed systems to control the harmful effects of thermal expansion. Thermal expansion tanks are available from Sears stores and through the Sears Service Centers. Contact the local plumbing inspector, water supplier and/or the Sears Service Center for assistance in controlling these situations. (For additional information, see the Troubleshooting Guide later in this manual.)

Temperature and Pressure Relief Valve

Explosion Hazard

• Temperature-pressure relief valve must comply with ANSI Z21.22-CSA 4.4 and ASME code.

• Properly sized temperature- pressure relief valve must be installed in opening provided.

• Can result in overheating and excessive tank pressure.

• Can cause serious injury or death.

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 24). 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 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 rating 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 rating 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 discharge line.

•Must terminate a maximum of six inches above a floor drain or external to the building. In cold climates, it is recommended that the discharge line be terminated at an adequate drain inside 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.

T&P Relief Valve and Pipe Insulation

1.	Locate the temperature and pressure relief valve on the water
	heater (also known as a T&P relief valve). See Figure 25.
2.	Locate the slit running the length of the T&P relief valve
	insulation.
3.	Spread the slit open and fit the insulation over the T&P relief
	valve. See Figure 25. Apply gentle pressure to the insulation
	to ensure that it is fully seated on the T&P Relief Valve. Once
	seated, secure the insulation with duct tape, electrical tape,
	or equivalent. IMPORTANT: The insulation and tape must not
	block the discharge opening or hinder access to the manual
	relief lever (Figure 25). Ensure a discharge pipe is installed
	into the T&P valve discharge opening per the instructions in
	this manual.
4.	Locate the hot water (outlet) & cold water (inlet) pipes to the
	water heater.
5.	Locate the slit running the length of a section of pipe insulation.
6.	Spread the slit open and slip the insulation over the cold water
	(inlet) pipe. Apply gentle pressure along the length of the
	insulation to ensure that it is fully seated around the pipe. Also,

1” MINIMUM

METAL DRAIN PAN

DRAIN

TEMPERATURE AND PRESSURE (T&P) RELIEF VALVE (OPTIONAL TOP T&P RELIEF VALVE NOT SHOWN)

DISCHARGE PIPE

(DO NOT CAP OR PLUG)

DRAIN LINE 3/4” ID MINIMUM

6” MAXIMUM AIR GAP

	ensure that the base of the insulation is flush with the water
	heater. Once seated, secure the insulation with duct tape,
	electrical tape, or equivalent.
7.	Repeat steps 5 and 6 for the hot water (outlet) pipe.
8.	Add additional sections of pipe insulation as needed.

T&P RELIEF VALVE INSULATION

MANUAL RELIEF

LEVER

T&P RELIEF

VALVE

T&P RELIEF VALVE

DRAIN LINE

FIGURE 24.

FIGURE 25.

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