23
Auxiliary limit family on this generation (shared diagnostic path with 22 and 33)
This code typically points to
- Auxiliary limit tripped
- Airflow issue
- Heat exchanger issue
Next checks to confirm
- Check auxiliary limit switches and wiring
- Public snippet says: if blower does not stop, expect 22, 23, or 33
Escalation
Safety interruption during heating
Reset behavior
Correct cause; reset applicable safeties.
Safety Critical
Immediate concern