33HIGH
Limit Switch Fault (Lennox)
Lennox furnace limit switch is open at startup or opens during operation, preventing normal function.
What This Error Code Means
The limit switch is open when it should be closed, or opens during blower operation indicating overheating.
Common Causes
- Blower motor not running at correct speed
- Dirty filter
- Limit switch failed open
- Restricted airflow
- High temperature rise across heat exchanger
Affected Brands
Lennox
How ROMA Heating Fixes This
- Check blower motor speed setting and operation
- Replace air filter
- Test limit switch continuity
- Inspect heat exchanger for blockages
- Verify temperature rise within specs
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Licensed Technicians
TSBC Gas License LGA0202903. Fully insured and WCB covered.
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