Lennox Code 36
Flame Sensor Error
What Lennox Code 36 Means
Flame Sensor Error – Furnace lights but shuts down after few seconds
Common Causes
- Flame sensor covered with soot
- Flame sensor connection loose
- Flame signal too weak
- Sensor wire corroded
- Sensor defective
First-Check: Step-by-Step Troubleshooting
- Remove flame sensor and clean gently
- Inspect flame sensor wire for damage
- Check all electrical connections
- Verify flame color is blue (not yellow)
- Test sensor resistance
- Replace sensor if damaged
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