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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-off_, 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 dosed. 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 _Ihnk
153.331020
2
8 inches
1274inches
74"Male
153.331050
5
11 inches 1474inches
74"Male
Expansion
Tank Sizing
Chart
Inlet*
Water
Expansion
Pressure
_I_nk
40psi
Capacity
50psi
Needed
60psi
70psi
80psi
Water Heater Capacity (Gallons)
30
40
50
66
80
2
2
2
5
5
2
2
2
5
5
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 tank's air pressure must be adjusted to match that
pressure, but must not be higher than 80 psi.
HOT
COLD
WATER HEATER
- COLD WATER
(3)
PRESSURE
, INLET FITTING
REDUCING
VALVEWITH
BY-PASS
O)
EXPANSION
TANK
(2)
PRESSUREGAUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
WATER HEATER
COLD WATER
INLET FITTING
FLOOR, CEILING
JOIST, ETC.
HOT
COLD
STRAPPING
(i)
EXPANSION
TANK
O)
PRESSURE
REDUCING
INLET COLD
VALVEWITH
WATER
BY-PASS
SHUTOFF
(z)
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.
18
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