For Your Information; Start Up Conditions; Operational Conditions - American Water Heater 300 Series Instruction Manual

START UP CONDITIONS

SMOKE/ODOR
It is not uncommon to experience a small amount of smoke and odor
during the initial start-up. This is due to burning off of oil from metal
parts, and will disappear in a short while.
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 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
release 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 qualified service
agency for assistance in controlling these situations.

OPERATIONAL CONDITIONS

SMELLY WATER
In each water heater there is installed at least one anode rod
(see Figure 1B and Figure 1C) for corrosion protection of the
tank. Certain water conditions will cause a reaction between this

FOR YOUR INFORMATION

rod and the water. The most common complaint associated with
the anode rod is one of a rotten egg smell in the hot water. The
smell is a 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
d. An excess of active hydrogen in the tank. This is caused by the
Smelly water may be eliminated or reduced in some water heater
models by replacing the anode rod(s) with one of less active material,
and then chlorinating the water heater tank and all water lines. Contact
the local water heater supplier or a qualified service agency for further
information concerning an Anode Rod Replacement Kit and this
chlorination treatment.
If the smelly water persists after the anode rod 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 rod 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.
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water heater (this harmless bacteria is nontoxic to humans).
corrosion protective action of the anode rod.