Closed system/thermal expansion, Temperature and pressure relief valve, T&p relief valve and pipe insulation – Kenmore POWER MISER 153.336433 User Manual

Page 22

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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,

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

DRAIN LINE

T&P RELIEF

VALVE

MANUAL RELIEF

LEVER

T&P RELIEF VALVE INSULATION

FIGURE 25.

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.

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

DRAIN LINE
3/4” ID
MINIMUM

DRAIN

1” MINIMUM

6” MAXIMUM
AIR GAP

METAL
DRAIN PAN

DISCHARGE PIPE
(DO NOT CAP OR PLUG)

FIGURE 24.

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