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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 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 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 or device to relieve the pressure built by thermal expansion in the
water

system. Expansion tanks are available for ordering through a

local plumbing contractor. Contact the local water heater supplier or
service agency for assistance in controlling these situations.

STRANGE SOUNDS

Possible noises due to expansion and contraction of some metal parts
during periods of heat-up and cool-down do not necessarily represent
harmful or dangerous conditions.

OPERATIONAL CONDITIONS

SMELLY WATER

In each water heater there is installed at least one anode rod (see
parts sections) 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” in the hot water. This odor is derived from hydrogen
sulfide 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 which has accumulated within the water

heater (this harmless bacteria is nontoxic to humans).

d. An excess of active hydrogen in the tank. This is caused by the

corrosion protective action of the anode.

Smelly water may be eliminated or reduced in some water heater
models by replacing the anode(s) with one of less active material, and
then chlorinating the water heater tank and all hot water lines. Contact
the local water heater supplier or service agency for further information
concerning an Anode Replacement Kit and this chlorination treatment.
If the smelly water persists after the anode replacement and chlorination
treatment, we can only suggest that chlorination or aeration of the
water supply be considered to eliminate the water problem.

Do not remove the anode leaving the tank unprotected. By
doing so, all warranty on the water heater tank is voided.

“AIR” IN HOT WATER FAUCETS

HYDROGEN GAS: Hydrogen gas can be produced in a hot water
system that has not been used for a long period of time (generally two
weeks or more). Hydrogen gas is extremely flammable and explosive.
To prevent the possibility of injury under these conditions, we
recommend the hot water faucet, located farthest away, be opened
for several minutes before any electrical appliances which are
connected to the hot water system are used (such as a dishwasher or
washing machine). If hydrogen gas is present, there will probably be
an unusual sound similar to air escaping through the pipe as the hot
water faucet is opened. There must be no smoking or open flame near
the faucet at the time it is open.

HIGH WATER TEMPERATURE SHUT OFF SYSTEM

A non-adjustable high temperature limit control operates before steam
temperatures are reached. The high limit is in the same area as the
upper thermostat and must be reset manually when it operates.
BECAUSE THE HIGH LIMIT OPERATES ONLY WHEN
ABNORMALLY HIGH WATER TEMPERATURES ARE PRESENT, IT
IS IMPORTANT THAT A QUALIFIED SERVICE AGENT BE CONTACTED
TO DETERMINE THE REASON FOR OPERATION BEFORE RESETTING.

ANODE ROD INSPECTION

The anode rod is used to protect the tank from corrosion. Most hot
water tanks are equipped with an anode rod. The submerged rod
sacrifices itself to protect the tank. Instead of corroding the tank,
water ions attack and eat away the anode rod. This does not affect
the water’s taste or color. The rod must be maintained to keep the tank
in operating condition.

Anode deterioration depends on water conductivity, not necessarily
water condition. A corroded or pitted anode rod indicates high water
conductivity and should be checked and/or replaced more often then
an anode rod that appears to be intact. Replacement of a depleted

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