Lennox · Furnace / HVAC
7 blinks Low flame signal
What this code means
The control board is sensing a flame, but the signal strength is weaker than expected.
Most likely causes
- Dirty burners or flame sensor
- Insufficient gas pressure
- Aging flame sensor losing sensitivity
What to try first
Clean the flame sensor and burners; if the code returns, gas pressure should be checked by a technician.
Safety note: if this code returns after one clean reset, stop resetting it — repeated lockouts usually mean a real fault that needs a licensed technician. Never bypass a safety switch.
FAQ
What does Lennox error code 7 blinks mean?
Low flame signal. The control board is sensing a flame, but the signal strength is weaker than expected.
Can I fix Lennox code 7 blinks myself?
Usually not. Clean the flame sensor and burners; if the code returns, gas pressure should be checked by a technician. If the code returns after one reset, it needs a licensed technician.
What causes Lennox code 7 blinks?
The most common causes are: dirty burners or flame sensor; insufficient gas pressure; aging flame sensor losing sensitivity.
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.