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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
INLET FITTING
REDUCING
VALVE WITH
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
VALVE WITH
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
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