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Troubleshooting
Guide
Start Up Conditions
THERMAL
EXPANSION
Water
supply systems may, because
of such events as high line
pressure, f[equent
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 _oint of
the water heater s temperature-pressure relief valve is reached, the
valve will relieve the excesspressure. The tempera_premure
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
dosed 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
_" Male
HOT
COLD
WATER HEATER
COLD WATER
;;_
INLET FITTING
O)
PRESSURE
REDUCING
VALVE
BY.PASS
0)
1
EXPANSION
TANK
O)
PRESSUREGAUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
WATER H EA1TcR
COLD WATER
INLET FITTING
FLOOR, CIEIUNG
joist, ETC.
HOT
COLD
STRAPPING
(I)
EXPAN_ON
0)
PRESSURE
REDUCING
INLET COLD
VALVE WITH
WATER
BYPASS
SHUTOFF
Expansion Tank Sizing Chart
Water Heater Capacity (Gallons)
Inle_
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
*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 tanks air pressure must be adjusted to match that
pressure, but must not be higher than 80 psi.
(2)
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
harmful or dangerous conditions.
18
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