Lennox · Furnace / HVAC
6 blinks Soft lockout — repeated ignition or flame-sensing failure
What this code means
The furnace tried to establish and hold a flame multiple times and failed, so it locked out.
Most likely causes
- Weak or dirty flame sensor
- Faulty gas valve
- Low or unstable gas pressure
What to try first
Clean the flame sensor rod with fine sandpaper or steel wool, then attempt one reset.
Good news: this one is often fixable without a service call. If it persists after the steps above, have it looked at.
Find the part on Amazon →FAQ
What does Lennox error code 6 blinks mean?
Soft lockout — repeated ignition or flame-sensing failure. The furnace tried to establish and hold a flame multiple times and failed, so it locked out.
Can I fix Lennox code 6 blinks myself?
Often, yes. Clean the flame sensor rod with fine sandpaper or steel wool, then attempt one reset.
What causes Lennox code 6 blinks?
The most common causes are: weak or dirty flame sensor; faulty gas valve; low or unstable gas pressure.
Other Lennox furnace codes
All Lennox furnace error codes →
Other furnace brands: Trane · Carrier · Goodman · Amana · American Standard · Rheem · Bryant · Generic · Nest
This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.