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Start Up Conditions
Thermal Expansion
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.
See Figure 41.
Thermal Expansion Tank Specifications
Model
Number
153.331020
153.331050
Tank
Capacity
In Gallons
2
5
Dimensions Pipe
in Inches Fitting
Diameter Len£1th On Tank
8 (203 mm) 12-3/4 (323 mm) 3/4" Male
11 (279 mm) 14-3/4 (375 mm) 3/4" Male
TABLE 6
Expansion Tank Sizing Chart
Expansion
Tank
Capacity
Needed
Inlet*
Water
Pressure
40psi
50psi
60psi
70psi
80psi
Water Heater Capacity (Gallons)
30 40 50 66 82
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
TABLE 7
*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.
WATER HEATER (3)
HOT COLD/ COLD WATER PRESSURE
r....--w.-. _- -...._ INLET FITTING REDUCING
VALVE WITH
BY-PASS
I I
WATER HEATER
COLD WATER
INLET FITTING
(2)
PRESSURE GAUGE INLET COLD
WATER SHUT-OFF
RECOMMENDED INSTALLATION
(VERTICAL MOUNTING)
FLOOR, CEILING JOIST, ETC.
HOT
I I
COLD
STRAPPING
(3)
PRESSURE
REDUCING
VALVE WITH
(1) BY-PASS
EXPANSION /
.,I t
PRESSURE GAUGE-- INLET COLD
WATER SHUT-OFF
ALTERNATE RECOMMENDED INSTALLATION
(HORIZONTAL MOUNTING)
FIGURE 41.
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 within the burner area
during heating and cooling periods and should be considered
normal. See "Condensation" section.
Draft Hood Operation
Check draft hood operation by performing a worst case
depressurization of the building. With all doors and windows
closed, and with all air handling equipment and exhaust fans
operating such as furnaces, clothes dryers, range hoods and
bathroom fans, a match flame should still be drawn into the draft
hood of the water heater with its burner firing. If the flame is not
drawn toward the draft hood, shut off water heater and make
necessary air supply changes to correct.
33