Standby-generator fuel supply delivers specified fuel type, pressure and volume. Related symptoms include overcrank, underspeed, RPM loss or loaded shutdown. Those symptoms do not prove the component failed: verify shutoff, LP level and supplier status; do not adjust pressure. Check the external shutoff valve and the tank level without opening any cabinet.
What this covers
- natural-gas and LP generators
What it does not cover
Differential
Likely causes of “Standby-generator fuel supply”, and how to tell them apart
- 1
The fuel shutoff valve is closed or the LP tank is low
What separates it The engine cranks and does not fire, or it runs and dies, and the tank gauge is low or the valve is closed.
How to confirm Check the external shutoff valve and the tank level without opening any cabinet.
- 2
The fuel supplier or the utility gas has been interrupted
What separates it The problem began during a cold snap, an outage or after a delivery, and other gas appliances are affected.
How to confirm Check with the supplier or the gas utility.
- 3
Cold weather affects LP vaporisation
What separates it The generator struggles in very cold weather with a low tank, and improves when the tank is fuller or warmer.
How to confirm Compare the tank level and the temperature at the time of the fault.
- 4
The regulator, the line or the fuel system has a fault
What separates it The tank is full and the valves are open, yet the generator still shows an overcrank or underspeed alarm.
How to confirm This is licensed gas and generator service; do not adjust any pressure.
Before you touch a setting
Record this first — changing settings destroys the evidence
- The alarm code, the tank level and whether the shutoff valve is open.
- The fuel type and the temperature at the time.
- Whether the generator fails in the exercise cycle or only in outages.
Try in this order
0 of 2 completedTest before you replace
ReversibleVerify shutoff, LP level and supplier status; do not adjust pressure.
Weigh the repair
ReversibleReplacement difficulty for the standby-generator fuel supply is licensed gas/authorized generator service.
Stop boundary
When this stops being a self-service repair
- !Do not adjust fuel pressure or open the fuel system; this is licensed gas work.
- !Leave the area and call the gas supplier if you smell gas.
Evidence ledger
Sources behind this answer
Exact questions
Common questions
How full should a propane tank be for a standby generator?+
Keep it well above a low level, and ask your supplier about the level needed for the load and the cold weather your generator faces.
What does the fuel supply do?+
It provides gas to the generator engine. Low pressure or a closed valve can stop starting or cause stalling.
Could the fuel type matter?+
Yes. Natural gas and propane setups differ, so the unit must be set up for the fuel it uses.