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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
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 hexted water.
The water within the water heater tank expands as it isheated 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 temperatui'e-pressure
relief valve is not intended for the constant relief "ofthermal
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 Capaci W
Number
In Gal_ns
153.331020
2
153.331050
5
Dimensions
in Inches
Diameter
Length
8 inches
12_ inches
11 inches
14_ inches
Pipe Fitting
On Tank
3
n
Male
3
-
Male
HOT
COLD
WATERHEATER
COLDWATER
INLET FrrrlNG
0)
TANK
WATER HEATER
COLD WATER
INLET FITTING
HOT
COLD
0)
PRESSURE
REDUCING
VALVE WITH
BY-PASS
PRESSURE G AUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR, C EILING
JOLt, ETC.
STRAPPING
0)
EXPANSION
o)
PRESSURE
REDUCING
INLET COLD
VALVE WITH
WATER
Bv_PASS
SHUTOFF
Expansion
Tank Sizing
Chart
Expansion
Tank
Capacity
Needed
Inlet*
Water
Pressure
40psi
50psi
60psi
70psi
80psi
Water Heater Capacity
(Gallons)
i
I
30
40
50
66
[
82
2
2
2
5
5
2
2
2
515
I
2
2
5
515
2
2
5
5
I
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, but 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
parts during periods of heat-up and cool-down
do not represent
harmful
or dangerous conditions.
Condensation
causes sizzling and popping
with the burner area
during
heati,n_ and coolin_ periods and should
be considered
normal. See Condensation
section.
28
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