Heil furnace LED flashes 7 times; furnace may lock out, often after repeated failed ignition attempts.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety: Turn off power and gas before touching any burner or ignition components.
Steps to check:
- Inspect flame sensor and wiring: Locate the flame sensor rod at the burner. Ensure the ceramic insulator is intact and the wire is not frayed or touching metal surfaces. Reroute the wire if it is rubbing on sharp edges.
- Clean flame sensor: Remove the sensor and gently clean the metal rod with fine steel wool. Do not sand the ceramic. Reinstall securely.
- Check for stray flame: Observe the burners during operation. Flames should be stable and blue, not lifting off or rolling out. Unstable flame can confuse the flame sensing circuit.
- Reset furnace: Turn power off for 30 seconds, then back on to clear lockout and test.
When to call a pro: If the board continues to detect flame when there is none, or if flames are unstable, a technician should test microamp flame signal, gas pressure, and replace the control board or flame sensor as needed.