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Troubleshooting Guide
Start Up Conditions
THERMAL EXPANSION
Water supply systems may, because of such events as high line
pressure, frequent cut-offs, the effects of water hammer among
others, have installed devices such as pressure reducing valves,
check valves, back flowpreventers, erc...to control these types of
problems. When these devices are not equipped with an internal
by-pass, and no other measures are taken, the devices cause the
water system to be closed. As water is heated, it expands (ther-
mal expansion) and closed systems do not allow for the expan-
sion of heated water.
The water within the water heater tank expands asit is heated and
increases the pressure of the water system. If the relieving point of
the water heater s temperature-pressure relief valve is reached, the
valve will relieve the excesspressure. The temperature-pressure
relief valve is not intendedfor the constant relief of thermal
expansion. This is an unacceptable condition and must be cor-
rected.
It is recommended that any devices installed which could create a
closed system have a by-pass and/or the system have an expan-
sion tank to relieve the pressure built by 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.
Thermal Expansion Tank Specifications
Model Tank Capacity Dimensions in Inches Pipe Fitting
Number In Gallons Diameter Length On Tank
153.331020 2 8inches 12_inches _" Male
153.331050 5 11 inches 14_ inches _" Male
NOT COLD
HOT
WATER HEATER
COLD WATER
INLET FITTING
WATER HEATER (3)
COLD WATER PRESSURE
INLET FITTING REDUCING
VALVEWITH
BY-PASS
(2)
PRESSURE GAUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR, CEILING
JOIST,ETC.
STRAPPING
(i)
EXPANSION
(3)
PRESSURE
REDUCING INLETCOLD
VALVEWITH WATER
BY-PASS SHUTOFF
Expansion Tank Sizing Chart
Water Heater Capacity (Gallons)
Expansion
Tank
Capacity
Needed
Inlet*
Water
Pressure
40psi
50psi
60psi
70psi
80psi
30 _ 40 50 b 66 82
2 2 2 5 5
2 2 2 5 5
2 2 5 5 5
2 2 5 5 5
2 5 5 5 5
*Highest recorded inlet water pressure in a 24 hour period or
regulated water pressure.
NOTE= Expansion tanks are pre-charged with a 40 psi air
charge. If the inlet water pressure is higher than 40 psi, the
expansion tank's air pressure must be adjusted to match that
pressure, bur must not be higher than 80 psi.
PRESSUREGAUGE
ALTERNATE RECOMMENDED
INSTALLATION
(HORIZONTAL MOUNTING)
STRANGE SOUNDS
Possible noises due to expansion and contraction of some metal
_arts during periods of heat-up and cool-down do not represent
armful or dangerous conditions.
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