De Dietrich 7712220 ignition electrode

This is a De Dietrich ignition electrode, with manufacturer codes 7712220 and 336.946.068. Ignition electrodes of this type deliver the spark that ignites the fuel-air mixture in the burner. They are mounted so that the tip reaches into the flame zone and are connected to the ignition transformer, which is controlled by the burner control. Like all electrodes that live in the combustion area, these are consumable parts and should be inspected periodically for wear. When selecting a replacement ignition electrode, the key parameters are the overall length, the bend angle of the rod, the diameter and length of the ceramic insulator, the spark gap setting, and the type of mounting flange or screw fixing. The electrode must match the shape of the combustion head and the burner series it was originally designed for. Common failure modes include erosion of the metal tip, cracking of the ceramic insulator due to thermal shock, accumulation of soot that shorts the spark, and a gradual widening of the spark gap that delays or prevents ignition. During the burner startup sequence, the ignition transformer fires the electrode while the gas valve opens. If the flame is not established within the safety time, the burner control locks out. A worn or incorrectly gapped electrode can cause repeated lockouts. When replacing, check the condition of the mounting base and the high-tension lead for any damage. The ceramic must be clean and free of cracks, and the gap should be set to the value specified by the burner manufacturer.