Salem, VA Standby Generator Installation & Maintenance — Why Your Generac Won’t Start

Estimated Read Time: 11 minutes

Power can fail in the Roanoke Valley without warning. If your Generac generator won’t start, you need a fast, safe path back to dependable power. This guide walks through 10 common causes and fixes you can try today, plus when to call a licensed electrician. With proper maintenance, you can avoid repeat failures and protect your home during storms and outages.

Why Your Generac Will Not Start: The 10 Most Common Causes and Fixes

Standby systems are reliable, but they still need fuel, spark, air, and proper control signals. Before you begin, set the unit to OFF and pull the service disconnect if you will open panels. Safety always comes first.

1) The generator is in OFF or not in AUTO

Many no-start calls trace back to the control being set to OFF or not returned to AUTO after service or a utility interruption.

What to check:

• Look at the control screen or selector switch. It should read AUTO.
• If it’s OFF, turn it to AUTO and initiate a manual exercise.

Why it matters: In AUTO, the unit senses outages and starts automatically.

When to call: If AUTO is selected but the unit will not crank, there may be a control board or sensor issue.

2) Weak or dead battery

Generator batteries often fail after 3–5 years, or sooner in extreme temperatures.

What to check:

• Confirm battery age and condition. Corrosion on terminals is a red flag.
• Make sure the battery charger or trickle charger is powered.

Quick fix: Clean terminals, tighten connections, and replace aged batteries. A healthy 12V battery at rest should read about 12.6 volts or higher.

Pro tip: We recommend adding battery checks to your annual service so you’re never surprised during an outage.

3) Low fuel, empty tank, or closed fuel valves

Both natural gas and propane systems require proper pressure and flow.

What to check:

• Natural gas: Verify the gas supply is on and other gas appliances are working.
• Propane: Confirm tank levels and ensure the service valve is fully open.

Quick fix: Open closed valves and schedule fuel delivery if levels are low. For propane systems, check that regulators are not frozen or failing.

When to call: If the generator cranks but never fires, we should measure gas pressure under load.

4) Tripped breaker or emergency stop

A tripped breaker can prevent cranking or power output.

What to check:

• Inspect the generator’s internal breaker and any external emergency stop button.
• At the automatic transfer switch (ATS), confirm breakers are in the correct position.

Quick fix: Reset a tripped breaker once. If it trips again, stop and call us so we can identify the underlying issue.

5) Dirty air filter or clogged intake

Engines need clean airflow to start and run properly.

What to check:

• Inspect the air filter for dirt, oil, or pest damage.
• Clear debris around intake vents and louvers.

Quick fix: Replace dirty filters and maintain at least three feet of clearance around the enclosure.

6) Overdue oil change or incorrect oil level

Many standby generators will not start if oil levels are low or degraded.

What to check:

• Confirm oil levels are within the dipstick range.
• Review your maintenance history.

Quick fix: Top off oil using the manufacturer-recommended type and schedule an oil and filter change if overdue.

Hard fact: With proper maintenance, many home generators last 15–20 years. Without it, lifespan can drop to 8–10 years.

7) Spark issues: plugs, wires, or ignition components

If the engine cranks but won’t fire, spark issues may be the cause.

What to check:

• Look for cracked plug wires, loose boots, or fouled spark plugs.
• Inspect for rodent damage, which is common in quiet residential areas.

Quick fix: Replace worn plugs or damaged wires. Ignition modules should always be tested by a professional.

8) Fault codes or safety lockouts

Your control panel records alarms that prevent unsafe operation.

What to check:

• Read the fault code displayed.
• Turn the unit OFF, wait briefly, then return it to AUTO to clear transient faults.

When to call: Persistent fault codes often indicate sensor, wiring, or mechanical problems that require professional service.

9) Fuel quality problems

Moisture, icing, or pressure issues can prevent startup.

What to check:

• For propane systems, inspect regulators for icing or moisture.
• For natural gas, confirm steady pressure to the generator connection.

Quick fix: Clear ice buildup and replace failed regulators as needed.

10) Transfer switch or control wiring issues

If the ATS does not send the start signal, the generator will not run.

What to check:

• Inspect ATS control fuses and low-voltage wiring.
• Confirm breaker positions inside the transfer switch.

Important note: ATS diagnostics involve live electrical components. This work should always be handled by licensed electricians.

Simple Start-Up Checklist You Can Do Safely

• Confirm the unit is set to AUTO.
• Inspect battery terminals and charger power.
• Check fuel supply and valve positions.
• Reset tripped breakers once only.
• Inspect air filters and enclosure clearance.
• Review oil service history.
• Attempt a manual exercise.

If the generator still won’t start, take a photo of any fault codes and call us. We can often diagnose the issue over the phone and arrive prepared.

Maintenance That Prevents No-Start Emergencies

Generators are not set-and-forget systems. Preventive care is essential.

Professional tune-ups include:

• Full safety inspections of gas, exhaust, and electrical components
• Oil, filter, air filter, and spark plug service
• Battery testing and charger verification
• Control settings and exercise scheduling
• ATS inspection and load testing when applicable

When It’s Time to Call a Licensed Electrician

Contact us immediately if you notice:

• Gas leaks or regulator icing
• Repeated fault codes or overcrank alarms
• Breaker trips or heat at the ATS
• Rodent-damaged wiring
• Any issue involving live electrical circuits

Wisler Plumbing, Heating, Cooling & Electric provides 24/7 generator support throughout Roanoke, Salem, Vinton, Rocky Mount, and surrounding areas.

Special Offer

Free quote on generator installation and service for Roanoke-area homeowners. Ask about GoodLeap financing, including select 0% interest periods for qualified jobs.

Call (540) 426-1351 or schedule online at callwisler.com today.

In Summary

If your Generac generator won’t start, begin by checking AUTO mode, battery condition, fuel supply, breakers, filters, and oil level. While some issues are quick fixes, problems involving gas pressure, wiring, sensors, or transfer switches require professional service. We’re here to help protect your home with reliable, code-compliant solutions.

Ready to restore dependable backup power? Call Wisler Plumbing, Heating, Cooling & Electric at (540) 426-1351 or schedule service at callwisler.com.