B9 / Eb9
Estimated airflow from motor is lower than airflow requirement
This code typically points to
- Failed indoor blower motor
- Indoor fan motor not properly connected
- Too much static pressure
Next checks to confirm
- Check indoor-fan motor wiring/connectors
- Replace indoor-fan motor if needed
Escalation
Airflow deficiency affecting system performance
Reset behavior
Clears after airflow returns to requirement.
Service Soon
Schedule repair