b3
Circulator blower motor is operating in a power, temperature, or speed limiting condition
This code typically points to
- Blocked filters
- Restrictive ductwork
- Undersized ductwork
- High ambient temperatures
Next checks to confirm
- Check filters for blockage
- Check ductwork and remove obstruction
- Verify all registers are fully open
- Verify ductwork is appropriately sized and resize/replace if necessary
Escalation
Furnace operates at reduced performance; airflow delivered is less than expected
Reset behavior
Clears after limiting condition is removed.
Service Soon
Schedule repair