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TROUBLESHOOTING GUIDE
START UP CONDITIONS
Thermal Expansion
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 fl ow 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 is heated 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 relief 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 30.
Thermal Expansion Tank Specifi cations
Model
Number
Tank
Capacity
In Gallons
Dimensions
In Inches (mm)
Pipe
Fitting
On Tank
Diameter Length
153.331020 2 8 (203) 12-3/4 (323) 3/4” Male
153.331050 5 11 (279) 14-3/4” (375) 3/4” Male
Expansion Tank Sizing Chart
Expansion
Tank
Capacity
Needed
Inlet*
Water
Pressure
Water Heater Capacity (Gallons)
30 40 50 66 80
40 psi 2 2 2 5 5
50 psi 2 2 2 5 5
60 psi 2 2 5 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.
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.
FIGURE 30.
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 fl ame should still be drawn into the draft hood of the water
heater with its burner fi ring. If the fl ame is not drawn toward the
draft hood, shut off water heater and make necessary air supply
changes to correct.