The Bosch HVAC 8738722789 Ionization Electrode is a replacement flame-sensing component designed for compatible Bosch gas boilers and heating systems. It operates by detecting the electrical ionization current produced by a burner flame, allowing the control system to confirm proper combustion and maintain safe burner operation. This electrode is used in gas-fired boilers and related ... https://www.partshnc.com/bosch-hvac-8738722789-ionization-electrode