A.O. Smith 1700 GAS Supply Connections, GAS Supply Pipe Connections, GAS Pressure Requirements

GAS SUPPLY CONNECTIONS

GAS SUPPLY PIPE CONNECTIONS

Figure 41.  GAS SUPPLY PIPING

1.Make sure to install ground joint union for servicing.

In Canada – When using manual main shutoff to support the weight of the piping with valves, ensure that it is identified by the installer.

2.Install drip leg (sediment trap) per NFPA 54 for US and CAN B149.1 for Canada.

3.Support the piping with hangers, not by the boiler or its accessories. The gas valve and blower will not support the weight of the piping. Failure to comply could result in severe personal injury, death, or substantial property damage.

4.Purge all air from the gas supply piping.

5.Before setting the boiler in operation, check the boiler and its gas connection for leaks.

•Disconnect the boiler from the gas supply piping system during any pressure testing, at a test pressure in excess of 1/2 PSIG (3.5 kPa)

•The boiler must be isolated from the gas supply piping system by closing a manual shutoff valve during any pressure testing, at test pressures equal to or less than 1/2 PSIG (3.5 kPa).

Do not check for gas leaks with an open flame, instead use the bubble test. Failure to use the bubble test or check for gas leaks can cause severe personal injury, death, or substantial property damage.

6.Use pipe sealing compound compatible with propane gases. Apply sparingly only to male threads of the pipe joints so that pipe dope does not block gas flow.

Failure to apply pipe sealing compound as detailed in this manual can result in severe personal injury, death, or substantial property damage.

7.Make sure the maximum inlet gas pressure do not exceed the value specified. Minimum value specified is for input adjustment only.

Make sure to use two wrenches when tightening gas piping at the boiler, using one wrench to prevent the boiler gas line connection from turning. Failure to support the boiler gas connection pipe to prevent it from turning could damage gas line components. Do not use wrench on valve body as damage would occur.

GAS PRESSURE REQUIREMENTS

The maximum allowable gas supply pressure for this boiler is 14 inches w.c. (3.5 kPa). Install a positive lock-up gas pressure regulator in the gas supply line if inlet gas pressure can exceed 14 inches w.c. (3.5 kPa) at any time.

If a positive lock-up regulator is required follow these instructions:

1.Positive lock-up gas pressure regulators must be rated at or above the input Btu/hr rating of the boiler they supply.

2.Positive lock-up gas pressure regulator(s) should be installed no closer than 3 feet (1 meter) and no farther than 8 feet (2.4 meters) from the boiler’s inlet gas connection.

3.After installing the positive lock-up gas pressure regulator(s), an initial nominal supply pressure setting of 7 inches w.c. (1.7 kPa) while the boiler is operating is recommended and will generally provide good boiler operation. Some addition adjustment maybe required later to maintain a steady gas supply pressure.

4.When installing multiple boilers in the same gas supply system it is recommended that individual positive lock-up gas pressure regulators be installed at each unit.

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