Status LED flashes five times repeatedly, furnace will not start heating cycle
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 servicing. This fault can indicate unsafe burner or wiring conditions.
Steps to check:
- Inspect flame sensor wiring: Remove the burner access panel. Locate the flame sensor rod and its wire back to the control board. Check for damaged insulation, bare spots touching metal, or loose connections. Repair or replace as needed.
- Clean flame sensor: Remove the flame sensor and gently clean with fine steel wool. Reinstall firmly.
- Check ground and neutral: Verify the furnace cabinet is properly grounded and that the neutral wire is correctly connected at the control board. Loose or missing ground can cause false flame readings.
- Reset control: Restore power and gas, then reset the furnace by cycling power. Observe operation and LED status.
When to call a professional: If the false flame code persists, the integrated furnace control board or other components may be defective. A Trane technician should perform advanced diagnostics and replace the control board if necessary.