3-FLASHHIGH
Limit Switch Open (Generic)
Primary limit switch has opened during operation, indicating the furnace is overheating or the switch has failed.
What This Error Code Means
The limit switch detected plenum temperature exceeding the safe maximum, shutting down the burner.
Common Causes
- Dirty air filter
- Blower motor not running
- Return air restriction
- Limit switch failed
- Heat exchanger restricted
Affected Brands
LennoxCarrierTraneGoodmanRheemYorkBryant
How ROMA Heating Fixes This
- Inspect and replace air filter
- Test blower motor and verify airflow
- Check for closed dampers or registers
- Test limit switch operation
- Monitor temperature rise after repair
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Licensed Technicians
TSBC Gas License LGA0202903. Fully insured and WCB covered.
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