• Verify that the fuel shutoff valve is open (ON).
• If the valve is closed (OFF) or partially closed, the correct amount of fuel cannot reach the unit and may cause issues. 

The unit is capable of operating on Natural Gas (NG) or Liquid Propane (LP) and is set manually during installation in two places:

• Controller menu setting: The controller should be set to match the fuel source being used. 
  • How do I verify the correct fuel selection is selected for my generator?
• Fuel jet orientation: The fuel jets must be physically oriented to the correct fuel type.
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• Both the controller fuel selection and the fuel jet orientation must match the fuel source being used. 
  • Important: If your unit was not recently installed, these settings are unlikely to be incorrect. However, verifying them is still considered best practice to rule out a potentially user-resolvable issue. 

For units operating on Liquid Propane (LP)

• When LP levels drop below 30%, fuel pressure may be affected, which can cause operational issues. Check your LP fuel levels to verify you are above 30%. 

For units operating on Natural Gas (NG)

• Natural gas grids can be impacted during major outage events or construction. Contact your natural gas supplier to verify any known issues in your area. 
• Note: Most natural gas suppliers post outage or supply disruption alerts on their websites. 

• Improper fuel pressure can lead to operational alarms. However, due to the specialized equipment and safety considerations involved, fuel pressure checks must be performed by a professional. 
• Before considering fuel pressure, it's important to follow a systematic diagnostic process with a Generac IASD. Think of this like checking a low tire—before replacing it, you would first check the air pressure and see if it holds air. Similarly, fuel pressure should only be evaluated after ruling out other common causes like the fuel shutoff valve, fuel levels, and air intake. 
• If all other troubleshooting checks do not resolve the issue, work with your dealer to determine whether contacting your gas supplier to verify fuel pressure is the next logical step in the troubleshooting process.

If there is a sudden change in load, it may not be able to maintain the required speed. (i.e., large air conditioning unit powered on)

• If you utilize any load management systems, verify they work as expected. (Generac Load Manager, Smart AC Module)
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  • What is a Generac Load Manager (previously known as a Smart Management Module (SMM))?
• If the generator's speed fluctuates audibly, try running it without a load to determine if something in the house is pulling irregularly or too much power. 
• Remove non-essential loads
• If the engine speed issues continue without a load, consider the maintenance steps below or contact a Generac IASD for further diagnosis.

Overspped alarms can sometimes occur during a power outage, and troubleshooting should focus on key areas to help determine the cause. These alarms may be triggered by fuel-related issues, sudden electrical load changes, or problems with the load management system.

Note any sudden load changes:

• Sudden shift in power demand-such as multiple large appliances turning on or off- can cause the unit to overspeed. 

Verify Fuel supply:

• Ensure the fuel supply troubleshooting checks above are completed. 

Inspect any load management systems:

• If your system utilized load management devices, check for malfunctions or improper settings that could be affecting the unit's response to electrical demand. 

Run the unit with no load applied:

• If fuel checks are verified and the issue persists, try running the unit without any load (no appliances or devices drawing power).
• If the unit runs normally without load, the problem may be related to an excessive or improperly managed electric load. 

Prioritize essential loads:

• When reintroducing power to appliances, start with essential loads first. 
• Gradually add additional loads to see if a particular appliance or circuit is triggering the overspeed condition. 

If the overspeed alarm continues after completed these checks, or if you are unsure about any step, contact a Generac IASD for further diagnosis and repair.  

• Important Note: Anytime power transfer has occurred and the generator is under load, all loads must be disconnected before restarting. The generator must be allowed to reach full speed and "warm up" before reconnecting loads. 
  • How do I know if my generator is currently under load?

The generator does not exercise under load; consider fuel and maintenance-related checks.

Questions to ask

• Check for repeated behavior.
• If your unit consistently triggers an overspeed alarm during exercise, note the conditions surrounding the unit's exercise time/ time of year. 
• Are you able to start the unit manually after receiving the fault?
• Contact a Generac IASD.

• Inspect Airfilter: During cold weather, moisture can freeze in the air filter, preventing adequate airflow to the engine.
• Snow buildup can also block airflow around the filter and cause this warning. Snow must be cleared from around the unit.
• See the What do I do when I expect a snow storm, or if there is snow building up around the unit? article for more information.

Seasonal Weather and environmental factors

• In some geographic areas, seasonal changes can surface issues that were previously unnoticed.
• Extreme cold in areas that don't normally experience it can affect external systems that supply fuel to the unit, such as an external regulator not rated for a rare extreme cold snap for your area. 
• Slight fuel pressure deviations that do not cause problems in warmer months may result in noticeable issues during the coldest winter months - this is more common in newly installed units which did not meet all installation requirements and specifications. 

If an overspeed alarm occurs during installation, the issue is most commonly related to the fuel system. One of the most frequent causes for issues during installation is air trapped in the fuel lines, which can prevent fuel flow and lead to engine instability Troubleshooting should focus on fuel checks first, with loaded related considerations only if the issue occurs during a load test (simulated outage).

Fuel system basic checks:

• Preform basic user resolvable fuel system checks outlined in the troubleshooting section. 
• Ensure that air has been properly bed from the fuel lines by your installing gas company.  

Confirm fuel system compliance with installation requirements:

• The installer should coordinate with the gas provider to ensure the fuel system meets all specifications
• Ensure proper fuel system leaks test is preformed and fuel pressure is with in installation specification.
• Note: Fuel pressure and fuel system leak tests should be preformed by a licensed professional.

Evaluate load-related factors (If issues occurs during load testing):

• If the overspeed alarm happens only when a load is applied, such as during a simulated power outage trust, load management should be reviewed. 
• Work with your Generac IASD to determine if adjustments are needed for large appliances that may be activating simultaneously. 

Important warranty consideration:

• Issues caused by improper installation are not covered under warranty. Ensuring proper fuel system setup by a qualified professional is essential for reliable operation. If an overspeed alarm occurs during installation, contact your installer immediately to verify installation requirements.

Diagnosing intermittent issues can be challenging because they are difficult to consistently replicate. However, owners can assist in the process by identify patterns and noting key details when the issue occurs. This information helps Generac IASDs diagnosis the root cause more efficiently. 

Identifying patterns to assist in diagnosis

Does the issue occur during an outage with a load applied?

• Pay attention to whether the overspeed alarm happens when a specific appliances such as a pool heater or large air conditioning unit, are activated. 
• If the issue occurs when these high-power devices turn on, the problem may be related to load management or sudden electrical demand changes. 

Does the issue occur during exercise mode?

• If the unit experiences overspeed alarms while running without any load applied, focus on fuel system factors. 

Seasonal Weather and environmental factors

• In some geographic areas, seasonal changes can surface issues that were previously unnoticed.
• Extreme cold in areas that don't normally experience it can affect external systems that supply fuel to the unit, such as an external regulator not rated for rare extreme cold for your area. 
• Slight fuel pressure deviations that do not cause problems in warmer months may result in noticeable issues during the coldest winter months - this is more common in newly installed units which did not meet all installation requirements and specifications. 
• If the issue coincides with seasonal shifts, it's important to discuss these conditions with your Generac IASD to determine if adjustments are needed. 

Have there been any changes to your fuel system?

• Significant changes in fuel demand, such as adding large gas appliances may impact your system.

Important note: This information is intended only to help owners provide useful context to a Generac IASD technician when diagnosing difficult-to-replicate errors. It is not a self-diagnosis guide. Diagnosing and resolving intermittent overspeed alarms require specialized tools and expertise, and a Generac IASD should always be consulted for proper evaluation. 

• When issues occur within the first year, it may suggest that aspects related to the installation should be considered as potential factors. Certain components may not show problems immediately, but issues can surface when specific circumstances arise due to seasonal changes and weather conditions. 

• When issues occur after the first year, it may suggest that aspects related to routine maintenance should be considered as potential factors.  Over time, regular wear and changes in usage conditions can make proper maintenance essential to prevent problems.