Closed Water Systems; Thermal Expansion; Temperature-Pressure Relief Valve - Kenmore 153.331350 Use & Care Manual

In addition to using lowest possible temperature
setting that satisfies demand of application, a
mixing valve should be installed at water heater
(see Figures 39 and 40) or at hot-water taps to
further reduce system water temperature.
Mixing valves are available at plumbing supply
stores. Consult a Qualified Installer or Service
Agency. Follow mixing valve manufacturer's
instructions for installation of the valves. Before
changing the factory setting on the thermostat,
read the "Temperature Regulation" section in this
manual.
Property Damage Hazard
• Avoid water heater damage.
• Install thermal expansion tank if necessary.
• Do not apply heat to cold water inlet.
• Contact qualified installer or service agency.
Temperature-Pressure Relief Valve
Closed Water Systems
Water supply systems may, because of code
requirements or such conditions as high line
pressure, among others, have installed devices
such as pressure-reducing valves, check valves,
and back flow preventers. Devices such as these
cause the water system to be a closed system.
Thermal Expansion
As water is heated, it expands (thermal expansion).
In a closed system, the volume of water will
increase. As the volume of water increases, 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.)
Explosion Hazard
• Temperature-pressure relief
valve must comply with ANSI
Z21.22-CSA4.4 and ASME
code.
• Properly sized temperature-
pressure relief valve must be
installed in opening provided.
• Do not plug, block, or cap the
discharge line.
• Failure to follow this warning
can result in excessive tank
pressure, serious injury or
death.
This water heater is provided with a properly
rated/sized and certified combination
temperature-pressure relief valve (T&P valve)
by the manufacturer. The valve is certified by
a nationally recognized testing laboratory that
maintains periodic inspection of production of
listed equipment of materials as meeting the
requirements for Relief Valves for Hot Water
Supply Systems, ANSI Z21.22-CSA 4.4, and the
code requirements of ASME.
If replaced, the new T&P valve must meet the
requirements of local codes, but not less than a
combination temperature-pressure relief valve
rated/sized and certified as indicated in the above
paragraph. The new valve must be marked with a
maximum set pressure not to exceed the marked
hydrostatic working pressure of the water heater
(150 psi = 1,035kPa) and a discharge capacity not
less than the water heater Btu/hr or kW input rate
as shown on the water heater's model rating plate.
For safe operation of the water heater, the
temperature-pressure relief valve must not be
removed from its designated opening nor plugged.
The T&P valve must be installed directly into the
fitting of the water heater designed for the relief
valve. Install discharge piping so that any discharge
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