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TROUBLESHOOTING
Start Up Conditions
THERMAL EXPANSION
Water supply systems may, because of such events as high line
pressure, frequent cut-offs, the effects of water hammer among
others, have installed devices such as pressure reducing valves,
check valves, back 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 the 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 to relieve the pressure built by thermal expansion
in the water system. 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.
Thermal Expansion Tank Specications
Tank Dimensions Pipe
Model Capacity
in Inches Fitting
Number In Gallons Diameter Length On Tank
153.331020 2 8 (203 mm) 12-3/4 (323 mm) 3/4” Male
Expansion Tank Sizing Chart
Expansion Inlet* Water Heater Capacity (Gallons)
Tank Water
Capacity Pressure 6 10 20 30
Needed 40-80 psi 2 2 2 2
*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 29.
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 will 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 sulde 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.