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Start Up Conditions NOTE: Expansion tanks are pre-charged with a 40 psi air
charge. If the inlet water pressure is higher than 40 psi, the
THERMAL EXPANSION expansion tank's air pressure must be adjusted to match
that pressure, but must not be higher than 80 psi.
Property Damage Hazard
• Avoid water heater damage.
• Install thermal expansion tank or device if necessary.
• Contact qualified installer or service agency.
As water is heated, it expands (thermal expansion). In a closed
system, the volume of water wilt grow. As the volume of water
grows, there wilt be a corresponding increase in water pressure
due to thermal expansion. Thermal expansion can cause
premature tank failure (leakage). This type of failure is not
covered under the limited warranty. Thermal expansion can also
cause intermittent temperature-pressure relief valve operation:
water discharged from the valve due to excessive pressure build
up. The temperature-pressure relief valve is not intended for the
constant relief of thermal expansion. This condition is not covered
under the limited warranty.
A properly-sized thermal expansion tank should be installed
on all closed systems to control the harmful effects of 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.
Table 2: Thermal Expansion Tank Specifications
Model Tank
Number
153.331020
153.331050
2
5
Dimensions
in Inches
Diameter Length
8 (203 mm) 12-3/4" (323 mm)
11 (279 rara) 14-3/4" (375 ram)
Pipe
Fitting
On Tank
3/4"Male
3/4"Male
Table 3: Expansion Tank Sizing Chart
Inlet* Water Heater Capacity
Water (Gallon)
Pressure
30 40 50 66 82
Expansion
Tank
Capacity
Needed
40psi
50psi
60psi
70psi
80psi
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.
HOT COLD
COLD WATER PRESSURE
INLET FITTING REDUCING
VALVE WITH
BY-PASS
6INCH
MAXIMUM AIR GAPt__
INLET COLD
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
WATER HEATER FLOOR, CEILING
COLD WATER JOIST, ETC,
INLET FITTING
HOT COLD STRAPPING
PRESSURE
REDUCING INLET COLD
VALVEWlTH WATER
BYPASS SHUTOFF
6INCH
PRESSURE GAUGE
ALTERNATE RECOMMENDED
INSTALLATION
(HORIZONTAL MOUNTING)
FIGURE 43.
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.
Operational Conditions
SMELLY WATER
In each glass-lined water heater there is installed one anode
rod (see parts section) for corrosion protection of the tank.
Certain water conditions wilt cause a reaction between this rod
and the water. The most common complaint associated with the
anode rod is one of a "rotten egg smell." This odor is derived
from hydrogen sulfide gas dissolved in the water. The smell is
the result of four factors which must all be present for the odor
to develop:
A. A concentration of sulfate in the supply water.
B. Little or no dissolved oxygen in the water.
C. A sulfate reducing bacteria within the water heater. (This
harmless bacteria is non-toxic to humans.)
D. An excess of active hydrogen in the tank. This is caused by
corrosion protective action of the anode.
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