b9
Low indoor airflow
This code typically points to
- Blocked filters
- Restrictive ductwork
- Undersized ductwork
Next checks to confirm
- Check filters for blockage
- Check ductwork for restriction or obstruction
- Correct duct sizing issue as required
Escalation
Furnace operates at reduced performance or airflow below requirement
Reset behavior
Clears when airflow deficiency is corrected.
Service Soon
Schedule repair