What to Do When Your Standby Generator Won't Start
When the power goes out, your generator should be ready. If it isn't, here are a few things you can safely check before scheduling a service call.
There's never a convenient time for your home standby generator to refuse to start. Whether it's a summer monsoon, a winter storm, or an unexpected utility outage, a generator that won't run defeats the whole purpose of owning one.
The good news is that many no-start conditions have simple causes. Before calling for service, here are a few things every homeowner can check.
1. Is the Generator in AUTO?
It may sound obvious, but this is one of the most common reasons a standby generator doesn't start during a power outage.
Make sure the controller is set to AUTO. If it's OFF, the generator won't automatically respond when utility power is lost.
It's surprisingly easy for someone to leave the controller in the wrong position after testing the generator or performing maintenance.
2. Is There a Fault Code?
Most modern Generac home standby generators will display a fault code when they detect a problem.
If the controller has a red light or is displaying an alarm, write down the fault code before attempting to clear it. That information can be extremely helpful when diagnosing the problem.
You can try resetting the alarm, but if the same fault immediately returns, there's an underlying issue that needs to be corrected—not simply reset.
3. Check the Battery
Every automatic start depends on a healthy battery.
If the generator only clicks, cranks very slowly, or doesn't crank at all, the battery could be weak or nearing the end of its service life. Corroded battery terminals can also prevent proper starting.
Most standby generator batteries last about three to four years and should be inspected during annual maintenance.
4. Verify the Fuel Supply
If your generator runs on natural gas or propane, make sure the fuel supply hasn't been interrupted.
Check that:
- The gas shutoff valve is fully open.
- Your propane tank has adequate fuel.
- There hasn't been any recent gas work performed on your home.
If the engine cranks but won't start, a fuel supply issue is one possible cause.
5. Check the Auxiliary Shutoff Switches
Most standby generators installed under the 2017 National Electrical Code (NEC) or later include external emergency shutdown switches, which Generac refers to as Auxiliary Switches.
Most residential installations have two of them:
- One is located outside of the generator enclosure.
- The other is located inside the generator enclosure.
If either switch has been turned OFF—whether intentionally or by accident—the generator will not start and will typically display **Error Code E2800 (Auxiliary Shutdown)**.
6. Has the Generator Been Exercising?
Your generator is designed to exercise each week automatically. This scheduled run keeps the engine lubricated, charges the battery, and verifies the system is ready for the next outage.
If you realize you haven't heard your generator exercise in several weeks, don't ignore it. A missed exercise cycle is often an early indication that something isn't right and should be investigated before the next power outage.
Avoid Guessing
If your generator repeatedly attempts to start without running, avoid continually trying to restart it or randomly replacing parts based on something you found online.
Modern standby generators use sophisticated electronic controls and multiple safety systems. Replacing parts without proper testing often costs more than having the problem diagnosed the first time correctly.
When It's Time to Call a Professional
If you've confirmed the generator is in AUTO, the battery appears healthy, fuel is available, the auxiliary shutdown switches are in the correct position, and the controller continues displaying a fault, it's time to schedule service.
An experienced standby generator technician can determine whether the problem involves the fuel system, ignition system, sensors, wiring, controller, or another component.
The Best Way to Prevent a No-Start Condition
The best repair is the one you never need.
Annual preventive maintenance is the best way to reduce the chances of your generator failing when you need it most. A comprehensive service includes inspecting critical components, changing required maintenance items, verifying proper operation, and identifying potential problems before they become costly repairs.
At On Demand Power, we specialize in residential home standby generators throughout the East Valley. Our annual maintenance service is designed to help ensure your generator is ready when the lights go out.
Because when the power fails, that's the worst possible time to discover your generator wasn't ready.
