Bryant Furnace Code 21.1
Hard lockoutShown as: 2 short flashes, 1 long flash
24 VAC was sensed on the gas valve when it should not be there. The control turns off and waits before retrying.
Manual wording: “21.1 24VAC sensed on gas valve when shouldn't be. - Turn off power and wait 5 minutes to retry.”
Documented for: 926TC, 912SE
Likely causes, most common first
- Stuck-closed gas valve relay on the control board
- Miswire or short at the gas valve wire
When to call a technician
This code means the board may not be able to keep the gas valve shut. Turn the furnace off at the service switch and call a technician.
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