A.O. Smith ProMax GPDX-50, Instruction Manual, Page: 14 / 36

14
line, and (2) the water manually discharged will not cause any bodily
injury or property damage because the water may be extremely hot.
If after manually operating the valve, it fails to completely reset and
continues to release water, immediately close the cold water inlet
to the water heater, follow the draining instructions, and replace the
temperature-pressure relief valve with a new one.
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 inch water
column (2.6 kPa) for natural and 13 inch water column (3.2 kPa) for
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 National Fuel Gas Code (ANSI Z223.1/ NFPA-54)-current edition,
whichever applies. Copper and brass tubing and
fi ttings (except tin
lined copper tubing) shall not be used.
If the gas control valve/thermostat is subjected to pressures
exceeding 1/2 psi (14 inches of water column or 3.5 kPa), the
damage to the gas control valve/thermostat 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 appliances shut
“off” until the water heater installation is complete.
A gas line of suf fi cient 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/thermostat
to help prevent dirt and foreign materials from entering the gas
control valve/thermostat.
• A fl exible gas connector or a ground joint union between the shut
off valve and gas control valve/thermostat 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 (2,347 meters), input
rating should be reduced at the rate of 4 percent for each 1,000 feet
(305 meters) above sea level which requires replacement of the burner
ori
fi ce in accordance with the National Fuel Gas Code ANSI Z223.1/
NFPA 54-current edition. Contact your local gas supplier for further
information.
Failure to replace the standard ori fi ce with a high altitude ori fi ce when
installed could result in improper and inef fi cient operation of the
appliance, producing carbon monoxide gas in excess of safe limits,
which could result in serious injury or death. Contact your gas supplier
for any speci
fi c changes which may be required in your area.
Use pipe joint compound or Te fl on 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 psi (14 inches of water
column or 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 psi (14 inches of water column or 3.5 kPa).
Connecting the gas piping to the gas control valve/thermostat of
the water heater can be accomplished by either of the two methods
shown in Figures 12 and 13.