Viessmann Ionization Electrode 7839451

The ionization electrode (with gasket) is a Viessmann flame-monitoring component for selected Vitodens 200-W and Vitodens 222-F gas boilers. It sits in the combustion circuit and provides the ionization signal the control unit uses to confirm that a flame is present. The electrode is supplied with its gasket for refitting at the burner.

• The boiler repeatedly fails to establish or hold a flame and goes to lockout.
• Flame detection is intermittent, causing short cycling or unexplained shutdowns during a demand.
• The electrode probe or its ceramic insulator shows cracking, heavy contamination or corrosion.
• The gasket at the electrode mounting point is perished, brittle or leaking.

• Confirm the appliance model and serial number against the fit list above, as fitment is serial-number specific.
• Inspect the existing electrode and gasket condition before ordering to confirm the fault lies with flame sensing rather than ignition.
• Check that the burner and heat exchanger are cool and the gas supply is isolated before any removal work.
• Refer to the appliance manufacturer's instructions for the correct removal and refitting procedure and torque guidance.