PB Heat DE manual Gas Piping

GAS PIPING

5.GAS PIPING

1.Size and install the gas supply piping properly in order to provide a supply of gas sufficient to meet the maximum demand without undue loss of pressure between the meter and the boiler.

2.Determine the volume of gas to be provided to the boiler in cubic feet per hour. To obtain this value, divide the Btu per hour rating (on the boiler rating plate) by the heating value of the gas in Btu per cubic feet. Obtain the heating value of the gas from the gas supplier. As an alternative, use Table 5.1 or

5.2on the next page to obtain the volume of gas to be provided to the boiler.

3.Use the value obtained above as the basis for piping sizing. Size the gas piping in accordance with Table

5.3.Consult the National Fuel Gas Code ANSI Z223.1/NFPA 54 and or CAN/CSA B149.1, Natural Gas and Propane Installation Code for proper sizing options.

4.Locate the drop pipe adjacent to, but not in front of the boiler.

5.Install a sediment trap. See Figure 5.1. Locate a tee in the drop pipe at same elevation as the gas inlet connection to the boiler. Extend the drop pipe to a pipe cap.

6.Install a ground joint union ahead of the gas control assembly to permit servicing of the control. Some local codes require an additional service valve when using the combination gas controls. If your code requires such a valve, a suggested location is shown in Figure 5.1.

WARNING

Use a pipe joint sealing compound that is resistant to the action of liquefied petroleum gas. A non-resistant compound may lose sealing ability in the presence of this gas, resulting in a gas leak and fire or explosion potential.

7.Check piping for leaks.

Use an approved gas detector, a non-corrosive leak detection fluid or other leak detection method. If leaks are found, turn off all gas flow and repair as necessary.

WARNING

When checking for leaks, do not use matches, candles, open flames or other methods that provide a source of ignition. This can ignite a gas leak, resulting in fire or explosion.

Figure 5.1: Gas Connection to Boiler

8.Disconnect the boiler and its individual shut-off valve from the gas supply piping system during any pressure testing of that system at test pressure in excess of 1/2 psig (3.5 kPa).

CAUTION

Do not subject the gas valve to more than 1/2 psi (3.5 kPa) pressure. Doing so may damage the valve.

Isolate the boiler from the gas supply piping system by closing its individual service valve during any pressure testing of the gas supply piping system at test pressure equal to or less than 1/2 psig (3.5 kPa).

9.Minimum permissible supply pressure for purposes of input adjustment:

Natural Gas	5.0″ W.C. (1.2 kPa)
LP Gas	11.0″ W.C. (2.7 kPa)

Maximum permissible supply pressure to the boiler

(Inches Water Column):	13.5″ W.C. (3.4 kPa)
Natural Gas
LP Gas	13.5″ W.C. (3.4 kPa)

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