How do I resolve a 'no heat' call using this board

The unit operates with a fixed setpoint of 31°F OFF and 54°F ON

Engineered for the rigors of commercial HVACR maintenance

While universal mounts exist

Lennox 12M66 Wiring Harness 318973-401 How do I resolve aThe Lennox 12M66 Wiring Harness (LB 99575) is a critical OEM electrical assembly engineered for precise signal routing and power distribution within residential and commercial HVAC systems. This genuine Lennox replacement part ensures seamless electrical communication between high voltage power supplies and low voltage control circuits, including connections for control boards, sensors, and motors. Designed to meet rigorous factory standards, the