Carrier Furnace Code 10.1
Hard lockoutShown as: Rapid flashing LED; the 3-digit display reads 10.1
L1 polarity fault. The polarity of the incoming 115 V power is reversed and the furnace will not operate.
Manual wording: “10.1 L1 POLARITY FAULT - Rapid flash LED. Polarity of incoming 115V power is reversed.”
Documented for: 58SC0B/58SC1B
Likely causes, most common first
- Line voltage (115 V) hot and neutral reversed at a junction
- If units are twinned, improper low-voltage (24 V) transformer phasing
When to call a technician
Correcting 115 V polarity means opening junction boxes and working on live wiring - call a licensed HVAC technician or electrician.
A Carrier furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Installation, Start-Up, Operating and Service and Maintenance Instructions - 58SC0B/58SC1B (Carrier, 58SC0B/58SC1B single-stage condensing gas furnace with 3-digit status display) · checked 2026-08-25