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Start Up Conditions
Thermal Expansion
As water is heated, it expands (thermal expansion). In a closed
system, the volume of water will grow. As the volume of water
grows, there will 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 37.
Thermal Expansion Tank Specifi cations
Tank
Model
Capacity
Number
In Gallons
Diameter
153.331020
2
8 (203 mm) 12-3/4 (323 mm) 3/4" Male
153.331050
5
11 (279 mm) 14-3/4 (375 mm) 3/4" Male
Expansion Tank Sizing Chart
Inlet*
Water
Pressure
Expansion
40psi
Tank
50psi
Capacity
60psi
Needed
70psi
80psi
*Highest recorded inlet water pressure in a 24 hour period or regulated
water pressure.
TROUBLESHOOTING GUIDE
Dimensions
in Inches
Fitting
Length
On Tank
Water Heater Capacity (Gallons)
30
40
50
66
2
2
2
5
2
2
2
5
2
2
5
5
2
2
5
5
2
5
5
5
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 WATER
OUT
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
Pipe
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.
Condensation
Whenever the water heater is filled with cold water, some
82
condensate will form while the burner is on. A water heater may
5
appear to be leaking when in fact the water is condensation.
5
This usually happens when:
5
•
A new water heater is filled with cold water for the first
5
time.
5
•
Burning gas produces water vapor in water heaters,
particularly high efficiency models where flue temperatures
are lower.
•
Large amounts of hot water are used in a short time and the
refill water in the tank is very cold.
35
MASSACHUSETTS: INSTALL
A VACUUM RELIEF IN COLD
WATER LINE PER SECTION
19 MGL 142.
THERMAL
EXPANSION TANK
COLD WATER
SUPPLY
TO
FIXTURES
PRESSURE
GAUGE
COLD WATER
INLET VALVE
COLD WATER
(SHUT-OFF VALVE)
FIGURE 37.
PRESSURE
REDUCING
VALVE WITH
BYPASS
IN
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Troubleshooting
