Gas Piping - A.O. Smith DIRECT VENTED GAS MODELS Installation And Operating Manual

GAS PIPING

WARNING
• Do not use water heater with
any gas other than the gas
shown on the rating plate.
• Excessive pressure to gas
control valve can cause serious
injury or death.
• Turn off gas lines during
installation.
• Contact qualified installer or
service agency.
WARNING
Explosion Hazard
Have a qualified technician make sure that the L.P.
gas operating pressure does not exceed 13" water
column.
Failure to do so can result in death, explosion, or
fire.
Make sure the gas supplied is the same type listed on the
model rating plate. The inlet gas pressure must not exceed
13 inch w.c. for natural gas and propane (LP) gas. 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). Copper or brass tubing and fi ttings (except that which
is certifi ed for gas usage) should not be used.
If the gas control valve/thermostat is subjected to
pressures exceeding 1/2 psi (14 inch w.c.), 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 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.
20
Fire and Explosion Hazard
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 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 manual gas 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. Repair and retest as required. When
fi nished, rinse off soapy solution and wipe dry.
Use pipe joint compound or Tefl on tape marked as being
resistant to the action of gases.
The appliance and its gas connection must be leak tested
before placing the appliance in operation.
The appliance and its individual manual gas 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 psi. It should be isolated from
the gas supply piping system by closing its individual
manual gas shut-off valve during any pressure testing of
the gas supply piping system at test pressures equal to
or less than 1/2 psi.
Connecting gas piping to the gas control valve/thermostat
of water heater can be accomplished by either of two
methods shown in Figure 13 & Figure 14.
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WARNING
Fire and Explosion Hazard
• Use joint compound or tape
compatible with propane.
• Leak test before operating
heater.
• Disconnect gas piping and
shut-off valve before pressure
testing system.