Bryant Furnace Code 12.1
StatusShown as: 1 short flash, 2 long flashes
"W" on at power up - normal operation. The blower runs for 90 seconds because the furnace was powered up during a call for heat, or the call ended during the blower on-delay.
Manual wording: “12.1 "W" ON at power up - Normal operation. Blower runs for 90 seconds, if unit is powered up during a call for het (R-W closed)”
Documented for: 926TC, 912SE
Likely causes, most common first
- Power was interrupted and restored while the thermostat was calling for heat
- The thermostat call ended during the blower on-delay period
What you can safely check yourself
- Nothing to fix - this is normal after a power blip or after switching the furnace back on
When to call a technician
If 12.1 appears repeatedly without any power outages, have a technician check for a loose 115 V connection or a failing blower door switch.
A Bryant furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation, Start-up, Operating and Service and Maintenance Instructions - 926TC (Bryant Heating & Cooling Systems, 926TC Preferred Series two-stage, variable-speed ECM multipoise condensing gas furnace) · checked 2026-08-25
- Installation, Start-up, Operating and Service and Maintenance Instructions - 912SE (Bryant Heating & Cooling Systems, 912SE Legacy Line 92% single-stage condensing gas furnace) · checked 2026-08-25