Gas Piping - A.O. Smith GDV Instruction Manual

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 (3.5 kPa) for natural and propane gas (L.P.). The
minimum inlet gas pressure shown on the rating plate is that
which will permit fi ring at rated input.
All gas piping must comply with local codes and ordinances or
with the current edition of the National Fuel Gas Code ANSI
Z223.1/NFPA 54 whichever applies. Copper and brass tubing
and fi ttings (except tin lined copper tubing) shall not be used.
If the gas control valve is subjected to pressures exceeding 1/2
psi (3.5 kPa), the damage to the gas control valve could result in
a fi re 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 appli-
ances shut "off" until the water heater installation is complete.
A gas line of suffi cient size must be run to the water heater.
Consult the current edition of the 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 (dirt leg) ahead of the gas control valve to
help prevent dirt and foreign materials from entering the gas
control valve.
• A fl exible 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
fl ame. Rinse off soapy solution and wipe dry.
When installed at elevations above 7,700 feet, input rating
should be reduced at the rate of 4 percent for each 1,000 feet
above sea level which requires replacement of the burner orifi ce
in accordance with the current edition of the National Fuel Gas
Code ANSI Z223.1/NFPA 54. Contact your local gas supplier for
further information.
Failure to replace the standard orifi ce with a high altitude orifi ce
when installed could result in improper and ineffi cient operation
of the water heater, producing carbon monoxide gas in excess
of safe limits, which could result in serious injury or death. Con-
tact your gas supplier for any specifi c changes which may be
required in your area.
Use pipe joint compound or Tefl on
tant to the action of petroleum [Propane (L.P.)] gases.
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 shall be discon-
nected 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 sup-
ply 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).
Connecting the gas piping to the gas control valve of the water
heater can be accomplished by either of the two methods shown
in Figures 7 and 8.
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