Furnace shows E14, indicating a flue gas temperature sensor fault

Safety first: Turn off power and allow the flue to cool before touching any components.

Steps:

• Locate flue sensor: Find the Danfoss flue gas temperature sensor inserted into the flue pipe near the furnace.
• Inspect mounting and wiring: Ensure the sensor is fully inserted and clamped. Check the cable for heat damage or melted insulation. Reroute away from hot surfaces if necessary.
• Check connector: At the control board, reseat the flue sensor connector and inspect for corrosion.
• Replace if faulty: If the sensor is physically damaged or tests open/short, replace it with the correct Danfoss flue gas sensor model.
• Reset and verify: Clear E14 and monitor flue temperature readings during operation to ensure they are within normal range.