Burnham 20_PV_I manual IV. Gas Piping

IV. Gas Piping

A.Size gas piping. Design system to provide adequate gas supply to boiler. Consider these factors:

1.Allowable pressure drop from point of delivery to boiler. Maximum allowable system pressure is ½ psig. Actual point of delivery pressure may be less; contact gas supplier for additional information. Minimum gas valve inlet pressure is listed on rating label.

2.Maximum gas demand. Table 1 lists boiler input rate. Also consider existing and expected future gas utilization equipment (i.e. water heater, cooking equipment).

Table 1: Rated Input
Boiler	Input Rate			Gas
	[cubic feet per hour]
Model				Connection
Number				Size
	Natural Gas		LP/Propane
203PV	62	24¾		½
204PV	96	38½		½
205PV	130	52		½
206PV	164	65¾		½

3.Length of piping and number of fittings. Refer to Table 2 for maximum capacity of Schedule 40 pipe. Table 3 lists equivalent pipe length for standard fittings.

4.Specific gravity of gas. Gas piping systems for gas with a specific gravity of 0.70 or less can be sized directly from Table 2, unless authority having jurisdiction specifies a gravity factor be applied. For specific gravity greater than 0.70, apply gravity factor from Table 4. If exact specific gravity is not shown choose next higher value.

For materials or conditions other than those listed above, refer to National Fuel Gas Code, NFPA 54/ ANSI Z223.1, or size system using standard engineering methods acceptable to authority having jurisdiction.

B.Connect boiler gas valve to gas supply system.

1.Use methods and materials in accordance with local plumbing codes and requirements of gas supplier. In absence of such requirements, follow National Fuel Gas Code, NFPA 54/ANSI Z223.1 and/or CAN/CGA B149 Installation Codes.

2.Use thread (joint) compounds (pipe dope) resistant to action of liquefied petroleum gas.

3.Install sediment trap, ground-joint union and manual shut-off valve upstream of boiler gas control valve and outside jacket. See Figure 6.

4.All above ground gas piping upstream from manual shut-off valve must be electrically continuous and bonded to a grounding electrode. Do not use gas piping as grounding electrode. Refer to National Electrical Code, ANSI/NFPA 70 and/or CSA C22 Electrical Code.

C.Pressure test. The boiler and its gas connection must be leak tested before placing boiler in operation.

1.Protect boiler gas control valve. For all testing over ½ psig, boiler and its individual shut-off valve must be disconnected from gas supply piping. For testing at ½ psig or less, isolate boiler from gas supply piping by closing boiler's individual manual shut-off valve.

2.Locate leaks using approved combustible gas detector, soap and water, or similar nonflammable solution. Do not use matches, candles, open flames, or other ignition source.

Figure 6: Recommended Gas Piping

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