John Wood Envirosense Power Direct Vent (May 2010 or later) - Manuel (Page 47)

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VENTING SYSTEM INSPECTION
At least once a year a visual inspection should be made of the venting
system. You should look for:
1. Obstructions which could cause improper venting. The
combustion and ventilation air flow must not be obstructed.
2. Damage or deterioration which could cause improper venting or
leakage of combustion products.
Be sure the vent piping is properly connected to prevent escape
of dangerous flue gasses which could cause deadly asphyxiation.
Obstructions and deteriorated vent systems may present serious
health risk or asphyxiation.
Chemical vapor corrosion of the flue and vent system may occur
if air for combustion contains certain chemical vapors. Spray can
propellants, cleaning solvents, refrigerator and air conditioner
refrigerants, swimming pool chemicals, calcium and sodium chloride,
waxes, bleach and process chemicals are typical compounds which
are potentially corrosive.
If after inspection of the vent system you found sooting or
deterioration, something is wrong. Call the local gas utility to correct
the problem and clean or replace the flue and venting before
resuming operation of the water heater.
ANODE ROD INSPECTION
Each water heater contains at least one anode rod, which will slowly
deplete (due to electrolysis) prolonging the life of the water heater
by protecting the glass-lined tank from corrosion. Adverse water
quality, hotter water temperatures, high hot water usage, hydronic
heating devices, and water softening methods can increase the rate
of anode rod depletion. Once the anode rod is depleted, the tank
will start to corrode, eventually developing a leak.
Certain water conditions will cause a reaction between the anode
rod and the water. The most common complaint associated with
the anode rod is a “rotten egg smell” produced from the presence
of hydrogen sulfide gas dissolved in the water. IMPORTANT: Do not
remove this rod permanently as it will void any warranties. A special
anode rod may be available if water odor or discoloration occurs.
NOTE: This rod may reduce but not eliminate water odor problems.
The water supply system may require special filtration equipment
from a water conditioning company to successfully eliminate all
water odor problems.
Artificially softened water is exceedingly corrosive because the
process substitutes sodium ions for magnesium and calcium ions.
The use of a water softener may decrease the life of the water
heater tank.
The anode rod should be inspected after a maximum of three years
and annually thereafter until the condition of the anode rod dictates
its replacement. NOTE: artificially softened water requires the anode
rod to be inspected annually.
The following are typical (but not all) signs of a depleted anode rod:
* The majority of the rods diameter is less than 3/8”.
* Significant sections of the support wire (approx. 1/3 or more of the
anode rod’s length) are visible.
If the anode rod show signs of either or both it should be replaced.
NOTE: Whether re-installing or replacing the anode rod, check for
any leaks and immediately correct if found.
In replacing the anode:
1. Turn off gas supply to the water heater.
2. Shut off the water supply and open a nearby hot water faucet to
depressurize the water tank.
3. Drain approximately 5 gallons of water from tank (Refer to
“Draining and Flushing” for proper procedures). Close drain valve.
4. Remove old anode rod.
5. Use Teflon® tape or approved pipe sealant on threads and install
new anode rod.
6. Turn on water supply and open nearby hot water faucet to purge
air from water system. Check for any leaks and immediately correct
any if found.
Restart the water heater as directed.
Figure: 36
PERIODIC MAINTENANCE