Carrier furnace code 12: Blower-On After Power-Up
Info — not a fault
What does code 12 mean on a Carrier furnace? The furnace was powered up in the middle of a call for heat (R-W closed), so the blower runs 90 seconds first. Informational, not a fault.
GOOD NEWS: THE FIRST CHECKS ARE FREE AND TAKE MINUTES.
Try these first — in this order
Wait 90 seconds.
Questions about this code
What does code 12 mean on a Carrier furnace?
The furnace was powered up in the middle of a call for heat (R-W closed), so the blower runs 90 seconds first. Informational, not a fault.
Does Carrier furnace code 12 mean I need a repair?
It's informational, not a fault. Wait for that to finish; if heating doesn't follow, note any new code and contact a technician.
How much does it cost to fix Carrier furnace code 12?
Code 12 doesn't call for a repair, so there's no cost tied to it. Any service cost depends on a separate problem if one appears.
Related symptoms
These symptoms can appear alongside this code. The link is an association, not a diagnosis, and code meanings vary by brand, model and control.
Applies to
58STA · 58STX
Different Carrier generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Same control platform, same code: Bryant furnace code 12 · Payne furnace code 12
Verified against Carrier 58STA/58STX Installation & Service Instructions (1106202L), p.37/48
Last verified 2026-07-06 · page updated 2026-10-07 · how we verify
Related Carrier furnace codes
These codes use the same status led — short + long flash codes system.