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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
i Tank CaDac ty Dimension,s in Inches
Pipe Fitting
[ Number
_
In Gallons
!Diameter"
Length
On Tank
1153.3310207
2
• 8inches
712_incbes
_;'Male
1153.33 050
i
5
i Hiochesil< inches Ma,e
HOT
COLD
i_,*ii=====,_1
WATER HEATER
COLD WATER
INLET FITTING
HOT
COLD
WATER HEATER
(3)
• COLD WATER
PRESSURE
INLET FITTING
REDUCING
VALVE WITH
BY-PASS
(i)
EXPANSION
TANK
(z)
PRESSUREGAUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR, CEILING
JOIST, ETC.
STRAPPING
(1)
EXPANSION
O)
PRESSURE
REDUCING
INLET COLD
VALVEWITH
WATER
BY-PASS
SHUTOFF
Expansion Tank Sizing Chart
i Inlet*
I
Water
Expansion
Tank
Capacity
Needed
Water Heater Capacity (Gallons)
Pressure
l
30
i
40
'
50
66
40psi
2
i
2
2
5
0psi [ 2 iT
5 1
76ps_
_
2
!
2
5
5
/
5
80psi
i
2
5
5
:
5
5
*Highest recorded inlet water pressure m a 24 hour period or
regulated water pressure.
NOTE:
Expansion tanks are we-charged
with a 40 psi air
charge. If the inlet water pressure is hi_her 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
heating
and cooling
periods
and should
be considered
normah
See "Condensation"
section.
28
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