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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.
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 supply system may, because of such events as high line
pressure, frequent cut-offs and the effects of water hammer 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 closed.
As water is heated, it expands (thermal
expansion) and closed systems do not allow for the expansion
of heated water.
The water within the water heater tank expands as it isheated and
increases the pressure of the water system. If the relieving point
of 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 corrected.
It is recommended
that any devices
installed
which could
create a closed system have a by-pass and/or the system have
an expansion
tank or device 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,
see Figure 34.
Thermal
Expansion
Tank Specifications
Tank
Dimensions
Pipe
Model
Capacity
in Inches
Fitting
Number
In Gallons
Diameter
Len£1th
On Tank
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
Capacity
Needed
Expansion
Tank Sizing
Chart
Inlet*
Water Heater Capacity (Gallons)
Water
Pressure
30
40
50
66
82
40 psi
2
2
2
5
5
50 psi
2
2
2
5
5
60 psi
2
2
2
5
5
70 psi
2
2
5
5
5
80 psi
2
5
5
5
5
*Highest recorded inlet water pressure in a 24 hour period or
regulated water pressure.
26
HOT
COLD
WATER HEATER
(3)
COLD WATER
PRESSURE
INLET FITTING
REDUCING
VALVE WITH
BY-PASS
(2)
PRESSURE GAUGE
INLET COLD
WATER
SHUT-OFF
RECOMMEN DED INSTALLATION
(VERTICAL
MOUNTING)
WATER HEATER
COLD WATER
INLET FITTING
HOT
I
f
FLOOR, CEILINGJOIS_ETC.
COLD
STRAPPING
/
t
PRESSURE GAUGE
INLETCOLD
WATERSHUT-OFF
ALTERNATE RECOMMENDED
INSTALLATION
(HORIZONTAL
MOUNTING)
FIGURE
34.
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 after 15 minutes of burner
operation, shut off water heater and make necessary air supply
changes to correct.
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Troubleshooting
