Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns.  

Fuel Line Facts

Gas pipe size will depend on the length of run from the source and how many elbows and T’s there are. We recommend contacting your gas provider, or a licensed plumber, and they will be able to size the gas line for you.

Environment

This article applies to the Guardian series and Next Generation series Air-Cooled Generator. If you have a liquid-cooled model, see your generator's spec sheet: Where can I find a user manual or other documentation for my home standby generator?
 

Fuel Line Sizing

Generac customer support cannot size gas lines, tanks, or regulators. We can provide BTU’s and fuel pressure in inches of water column, which will help your installer correctly size these items. (All BTU/inches of water column info can be found on spec sheets.) Fuel supplies should be sized based on 100% load.

A natural gas (NG) and liquid propane (LP) gas pipe sizing reference table can be found in the generator's installation manual. The tables are based on schedule 40 black pipe. If installing any other piping system, follow pipe sizing charts for the selected piping system. To locate an installation manual for a home standby generator, reference the Where can I find a user manual or other documentation for my home standby generator? article.

You will need to determine the following information about your generator to provide to your installer or dealer.

Note: These measurements are for air-cooled models manufactured in 2013 and newer. If you have a liquid-cooled model, or a generator that was manufactured prior to 2013, see your generator's spec sheet: Where can I find a user manual or other documentation for my home standby generator? 

1. The required fuel pressure in inches of a water column:

• Natural Gas: 3.5"-7" WC (.13-.25 PSI)

• Liquid Propane: 10-12” WC (.36-.43 PSI)

2. The fuel type (Liquid Propane or Natural Gas).

 

3. The required BTUs at 100% load:

• Natural Gas: ft³/hr x 1000 = BTU

• Liquid Propane: ft³/hr x 2500 = BTU

This information should be provided to the installer to determine the proper pipe sizing. See the How Can I Find a Generac Service Dealer in My Area? article for more information.

Where can I find charts?

Fuel sizing charts can be found in the installation manuals for each generator. To locate an installation manual, use the product lookup tool on Generac.com. See Where can I find an installation manual for my home standby generator? for more information.

Note: The charts below are offered as an example of information listed in the installation manuals. Gas line sizing should be performed by a certified service dealer or certified plumber.

NG pipe sizing

Pipe Size (in / mm)	For 5–7 in Water Column (1.24–1.74 kPa) Allowable Pipe Distances (ft/m)				For 3.5–5 in Water Column (0.87–1.24 kPa) Allowable Pipe Distances (ft/m)
	0.5/13	0.75/19	1/25	1.25/32	0.75/19	1/25	1.25/32	1.5/38
10 kW	10/3.1	60/18.3	200/61	750/228.6	20/6.1	60/18.3	175/53.3	—
14/18 kW	—	10/3.1	55/16.7	200/60.9	—	30/9.1	125/38.1	200/61
22–28 kW	—	10/3.1	30/9.1	115/35.1	—	10/3.1	60/18.3	125/38.1

LP gas pipe sizing

Pipe Size (in / mm)	For 10–12 in Water Column (2.49–2.99 kPa) Allowable Pipe Distances (ft/m)
	0.5/13	0.75/19	1/25	1.25/32
10 kW	30/9.1	175/53.3	400/121.9	—
14/18 kW	—	80/24.4	350/106.7	600/182.9
22–28 kW	—	40/12.2	175/53.3	550/167.6