1 flash
Limit switch open
This code typically points to
- Airflow restriction (dirty filter)
- Underfloor crossover duct collapse (common in manufactured homes)
- Blower issue
- High temperature rise
Next checks to confirm
- Verify filter and airflow first
- Inspect underfloor ducts (manufactured-home specific)
- Verify blower operation
- Verify limit circuit
Escalation
Recurring trips with correct airflow point toward limit or heat-exchanger issue.
Reset behavior
Clears when limit recloses.
Urgent
Fix now