John Wood Envirosense Power Direct Vent (May 2010 or later) - Manuel (Page 46)

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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
a v a i l a b l e f o r o r d e r i n g t h r o u g h a l o c a l p l u m b i n g
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: 50 GALLON UNIT” & “Figure 1C: 75 GALLON UNIT”
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. 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
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 rod.
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.
FOR YOUR INFORMATION