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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 flow preventers,
etc._to
control these types of
_roblems.
When these devices are not equipped
with an internal
y-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
Dimensions
in Inches
Pipe Fitting
Number
In Gallons
Diameter
Length
On Tank
153.331020
2
8 inches
12_ inches
_" Male
153.331050
5
11 inches
14_ inches
3/,,,Male
HOT
COLD
WATER HEATER
COLD WATER
INLET FITTING
HOT
COLD
WATERHEATER
(3)
• COLDWATER
PRESSURE
,
INLETFITTING
REDUCING
VALVE WITH
BY-PASS
O)
1
EXPANSION
TANK
(2)
PRESSURE G AUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR,CEILING
jols_, ETC.
STRAPPING
o)
PRESSURE
REDUCING
VALVE WITH
O)
B'_PASS
EXPANSION
INLET COLD
WATER
SHUTOFF
Expansion Tank Sizing Chart
Expansion
Tank
Capacity
Needed
Inlet*
Water
Pressure
40psi
50psi
60psi
70psi
80psi
Water Heater Capacity
(Gallons)
30
40
50
66
82
2
i
2
2
5
5
2
_
2
5
5
2_--_
5
5
5
2
2
_
5
5
5
21 7T5
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 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.
(2)
PRESSURE G AUGE
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
harmful or dangerous
conditions.
21
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