This is a troubleshooting bulletin for Carmel plug-in furnace models (AC2030TNA / TG2030TN).
"Limit switch not connected" or "Vent presence switch not activated" are root causes.
Check if "Hot surface igniter failed" or "Combustion fan not working."
Verify "Loose power cable or thermostat wire" or internal disconnections.
Inspect power connection stability and the DC jack behind the control module.
Described as a "Harmless glitch."
Results from excessive torque; requires proper installation technique.
The bulletin includes detailed corrective actions, installation pointers, and visual guides for proper front panel alignment - all sourced from Williams Engineering Department.
