De Dietrich 97955659 ionisation probe

This is an ionisation probe for use in gas burners that rely on flame rectification for flame proving. The probe generates a small rectified current through the flame, which the burner control interprets as confirmation that the burner has lit. It sits in the flame zone, typically alongside or opposite the ignition electrode. Parts of this type are consumable because the tip is exposed to high temperature and combustion by-products. Common reasons for replacement include a worn or eroded tip, a cracked ceramic insulator, or sooting that interferes with the electrical signal. Selection of a replacement probe depends on its physical dimensions—electrode length, bend angle, insulator diameter, and the gap between probe and burner mass—as well as the mounting arrangement and the burner series for which it was originally designed. The probe is identified by the manufacturer codes 97955659 and 336.946.005. When replacing, ensure the new probe matches the original in overall length and tip position so that the gap is correct; a drifting gap can delay ignition or cause a lockout.