FAQ - What does an error code 12 mean?
An error code 12 indicates a flame loss. This means that the unit is detecting a flame, but the flame is being extinguished during operation (weak flame).
Common issues associated with a 12 error code include:
1) Insufficient gas supply
2) Insufficient air supply
3) Debris on the flame sensor
It is recommended that you contact a servicer to troubleshoot this error code.