Gas Piping - A.O. Smith 185874-001 Instruction Manual

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 10.5" W.C.
for natural gas and 13" W.C. for propane (L.P.) gas. The minimum
inlet gas pressure shown on the rating plate is that which will permit
firing at rated input.
If the gas control valve is subjected to pressures exceeding 1/2 pound
per square inch (3.5 kPa), 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 drip leg (sediment trap) ahead of the gas control valve to help
prevent dirt and foreign materials from entering the 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.
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.
Use pipe joint compound or Teflon tape marked as being resistant
to the action of petroleum [Propane (L.P.)] gases.
The appliance and its gas connection must be leak tested before
placing the appliance in operation.
The appliance and its individual Shut-off valve shall be disconnected
from the gas supply piping system during any pressure testing of
that system at test pressures in excess of 1/2 pound per square inch
(3.5 kPa). It shall be isolated from the gas supply piping system
by closing its individual manual Shut-off valve during any pressure
testing of the gas supply piping system at test pressures equal to
or less than 1/2 pound per square inch (3.5 kPa).
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