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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.
GAS PIPING
Make sure the gas supplied is the same type listed on the
model rating plate. The inlet gas pressure must not exceed
14 inch water column (3.5kPa) for natural gas. The minimum inlet
gas pressure listed on the rating plate is for the purpose of input
adjustment. If the gas control valve is subjected to pressures
exceeding 1/2 pound per square inch (3.5kPa), the damage
to the gas control valve could result in a fire or explosion from
leaking gas.
If the main gas line shut-off serving all gas appliances is used, also
turn “OFF” the gas at each appliance. Leave all gas appliances shut
“OFF” until the water heater installation is complete.
A gas line of sufficient size must be run to the water heater.
Consult the current edition of National Fuel Gas Code ANSI
Z223.1/NFPA 54 and your gas supplier concerning pipe size.
There must be:
• A readily accessible manual shut off valve in the gas supply
line serving the water heater, and
• A sediment trap ahead of the gas control valve to help prevent dirt
and foreign materials from entering gas control valve.
• A flexible gas connector or a ground joint union between the
shut off valve and control valve to permit servicing of the unit.
Be sure to check all the gas piping for leaks before lighting the
water heater. Use a soapy water solution, not a match or open
flame. Rinse off soapy solution and wipe dry.
The minimum inlet gas pressure shown on the rating plate is that
which will permit firing at the rated input.
Water heaters covered in this manual have been tested and approved
for installation at elevations up to 7,700 feet (2,347 m) above sea
level. For installation above 7,700 feet (2,347 m), the water heater’s
Btu input should be reduced at the rate of 4 percent for each 1,000
feet (305 m) above sea level which requires replacement of the
burner orifice in accordance with the National Fuel Gas Code
ANSI Z223.1/NFPA 54. Contact your local gas supplier for further
information.
Failure to replace the standard orifice with the proper high altitude
orifice when installed at elevations above 7,700 feet (2,347 m)
could result in improper and inefficient operation of the appliance,
producing carbon monoxide gas in excess of the safe limits. This
could result in serious injury or death. Contact your local gas supplier
for any specific changes that may be required in your area.
The water heater and its gas connection must be leak tested
before placing the water heater in operation.
The water heater and its individual shut-off valve should be
disconnected from the gas supply piping system during any
pressure testing of that system at test pressures in excess of 1/2
