Maximum fuel pressure supplied to the generator’s demand regulator

Generac home standby generators use a demand regulator, which means they do not regulate the incoming fuel pressure. The regulator is not designed to withstand high pressures, so the incoming fuel pressure must meet the specifications below.

Environment

This article applies to Generac air-cooled home standby generators, including Guardian series and Next Generation (Next Gen) series models.

Regulator maximum pressure

The maximum pressure that should be supplied will be dependent on the fuel type.

• For natural gas: 3.5–7" WC (0.13–0.25 PSI).
• For liquid propane vapor: 10–12" WC (0.36–0.43 PSI).

For steps to measure and confirm the fuel pressure at the generator, see: How Do I Determine the Proper Fuel Pressure for My Air-Cooled Home Standby Generator?

Proper fuel pressure is important for correct generator operation. Pressure that is too high or too low can cause:

• Damage to the demand regulator.
• Damage to the fuel solenoid.
• The engine not starting.
• A rough running engine.
• The engine being unable to support a load.
• Premature engine failure.

Note: Failures due to an improper fuel supply are not warrantable. See What Does My Home Standby Generator Warranty Cover?

Disclaimer: Fuel supply evaluation, pressure testing, and regulator or fuel system adjustments should only be performed by an Independent Authorized Service Dealer (IASD) or a licensed tradesperson.