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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
Number
153.331020
153.331050
Tank Capacity
In Gallons
2
5
Dimensions in Inches
Diameter
Length
8 inches
12_ inches
11 inches 14_ inches
Pipe Fitting
On Tank
_" Male
_" Male
HOT
COLD
HOT
WATER HEATER
COLD WATER
INLET FITTING
WATERHEATER
• COLDWATER
O)
PRESSURE
INLET FrI'rlNG
REDUCING
VALVE WITH
BY-PASS
O)
1
EXPANSION
TANK
(z)
PRESSURE G AUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR, CEILING
IOlS_, ETC.
STRAPPING
O)
EXPANSION
o)
PRESSURE
REDUCING
VALVE WITH
BY-PASS
INLET COLD
WATER
SHUTOFF
i
Expansion Tank Sizing Chart
Water Heater Capacity (Gallons)
Inlet*
Water
Pressure
40psi
50psi
60psi
70psi
80psi
Expansion
30
40
50
66
82
Tank
2
2
2
5
5
Capacity
2
2
2
5
5
Needed
2
2
5
5
5
2
2
5
5
5
2
_
5
5
5
5
I
*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, but must not be higher than 80 psi.
(1)
PRESSURE G AUGE
ALTERNATE RECOMMENDED
INSTALLATION
(HORIZONI_L
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
narmful
or dangerous
conditions.
21
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