John Wood Direct Vent - Manuel (Page 28)

28 www. johnwoodwaterheaters .com
FOR YOUR INFORMATION
EXTERNAL DAMAGE
Do not operate the water heater until it has been fully
checked out by a qualifi ed technician, if the water heater:
• Has been exposed to fi re or damage.
• Displays evidence of sooting.
• Produces steam or unusually hot water.
If the water heater has been fl ooded it must be replaced.
START UP CONDITIONS
NEVER OPERATE THE HEATER WITHOUT FIRST
BEING CERTAIN IT IS FILLED WITH WATER AND A
TEMPERATURE AND PRESSURE RELIEF VALVE IS
INSTALLED IN THE RELIEF VALVE OPENING OF THE
HEATER. DO NOT ATTEMPT TO OPERATE HEATER
WITH COLD WATER INLET VALVE CLOSED.
Condensate
Whenever the water heater is fi lled with cold water, some
condensate will form while the burner is on. A water
heater may appear to be leaking when in fact the water is
condensate. This usually happens when:
a. A new water heater is fi lled with cold water for the
fi rst time.
b. Burning gas produces water vapour in water heaters,
particularly high efficiency models where flue
temperatures are lower.
c. Large amounts of hot water are used in a short time
and the refi ll water in the tank is very cold.
Moisture from the products of combustion condense on
the cooler tank surfaces and form drops of water which
may fall onto the burner or other hot surfaces to produce
a “sizzling” or “frying” noise.
Because of the suddenness and amount of water,
condensate water may be diagnosed as a “tank leak”.
After the water in the tank warms up (about 1-2 hours),
the condition should disappear.
Do not assume the water heater is leaking until there has
been enough time for the water in the tank to warm up.
An undersized water heater will cause more condensation.
The water heater must be sized properly to meet the
family’s demands for hot water including dishwashers,
washing machines and shower heads.
Excessive condensate may be noticed during the
winter and early spring months when incoming water
temperatures are at their lowest.
Good venting is essential for a gas fi red water heater
to operate properly as well as to carry away products of
combustion and water vapour.
Smoke/Odour
It is not uncommon to experience a small amount of
smoke and odour 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 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.
As water is heated, it expands (thermal expansion). As the
volume of water increases, there will be a corresponding
increase in water pressure due to thermal expansion.
Thermal expansion can cause premature tank failure
(leakage). This type of failure is not covered under the
limited warranty. Thermal expansion can also cause
intermittent temperature-pressure relief valve operation:
water discharged from the valve due to excessive pressure
build up. The temperature-pressure relief valve is not
intended for the constant relief of thermal expansion. This
condition is not covered under the limited warranty.
A properly-sized thermal expansion tank should be
installed on all closed systems to control the harmful
effects of thermal expansion. Contact a plumbing service
agency or your retail supplier regarding the installation of
a thermal expansion tank.