22
Main limit / dead-blower main-limit-open family on this generation
This code typically points to
- Main limit open
- Low airflow
- Overheating
- Blower not moving air
Next checks to confirm
- Check airflow, filter, blower operation, and limit circuit continuity
Escalation
If main limit circuit remains open >150 seconds, dead-blower logic can contribute to one-hour or hard-lockout behavior depending count
Reset behavior
Clears when limit and airflow issue are corrected; lockout resets per control rules.
Safety Critical
Immediate concern