Furnace starts ignition sequence but shuts down with E02, indicating flame is not detected or lost shortly after ignition.

Safety: Switch off power to the Viadrus furnace and close the gas cock before servicing. Wait for all hot surfaces to cool.

• Clean flame sensor: Locate the flame sensor rod (often combined with or next to the ignition electrode). Remove the mounting screw and gently clean the metal rod with fine steel wool or emery cloth until shiny. Do not sand the ceramic insulator. Reinstall securely.
• Check grounding: Ensure the burner assembly and gas valve manifold are firmly grounded to the furnace chassis. Tighten any loose ground screws and clean off rust or paint at the contact points.
• Inspect burner ports: Remove the burner ramp and check for blocked or corroded burner ports. Clean with a soft brush and compressed air. Do not enlarge the ports.
• Verify gas pressure: A licensed gas technician should measure inlet and burner manifold pressure at the Viadrus gas valve test ports and adjust according to the rating plate. Low pressure can cause weak or unstable flame.
• Control board check: If the flame sensor is clean and wiring is intact but E02 persists, the flame rectification circuit on the main control board or ignition module may be faulty. Replacement of the control board should be done by a qualified technician.