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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, etc._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 as it 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 excess pressure. The temperature-pressure
relief valve is not intended for 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
Number In Gallons
i
153•331020 2
153.331050 5
Dimensions in Inches
Diameter Length
8 inches 12_ inches
11 inches 14_ inches
Pipe Fitting
On Tank
_" Male
_" Male
HOT
COLA2
HOT
WATER HEATER
COLD WATER
INLET FITrlNG
COLD
WATERHEATER (3)
• COLDWATER PRESSURE
INLETFITTING REDUCING
VALVEWITH
BY-PASS
(I) 1
EXPANSION
TANK
(2)
PRESSURE GAUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR, CE|UNG
jols'_,ETC.
STRAPPING
11)
EXPANSION
(3)
PRESSURE
REDUCING INLETCOLD
VALVEWITH WATER
BY-PASS SHUTOFF
Expansion Tank Sizing Chart
Inlet* Water Heater Capacity (Gallons)
]Water
[Pressure 30 _ 40 [ 50 66_ 82
Expansion _si _ 2 : 2 _
Tank [50psi 2 __ 5 fi
Capacity
Needed 166psi 2 [2 , 5 5_ [_
70psi _2- I 5 5 i 5
80psi --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 me i,nlet water pressure is higher than 40 psi, the
expansion tanks air pressure must be adjusted to match that
pressure, but must not be higher than 80 psi.
{zl
PRESSURE GAUGE
ALTERNATE RECOMMENDED
INSTALLATION
(HORIZONTAL MOUNTING)
STRANGE SOUNDS
Possible noises due to expansion and contraction of some metal
parts during periods of heat-up and cool-down do not represent
narmful or dangerous conditions•
21