Replacement Sensor #3 (Boiler) for select: Vitodens 200-W WB2B, Vitodens 200 WB2/WB2A and Vitodens 100-W B1HA/B1KA/WB1A/WB1B/WB1Bc Series Residential Wall-Mounted Gas-Fired Condensing Boilers. This sensor is also compatible with the CombiPLUS Kit. Any adjustments, installations, service or maintenance must be completed by a licensed professional heating contractor who is qualified to work with hot water boilers. When ordering replacement parts, check with the manufacturer and provide the 16-digit boiler serial number or the 12-digit ASME/NB serial number to ensure a proper fit before purchasing.