12
Blower on after power-up
This code typically points to
- Normal response when powered during a heat call
- Normal response when R-W opens during blower on-delay
- Direct short in certain circuits can cause repetitive code-12 behavior
Next checks to confirm
- Verify whether unit was repowered mid-call before treating this as a fault
Escalation
None unless blower remains abnormal after the 90-second period.
Reset behavior
Blower runs 90 seconds, then control resumes normal sequence.
Informational
No action needed