GAS Piping

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.

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).