the S1-331-03009-000 is the direct manufacturer-specified upgrade for the discontinued 50A51-242 model

Thermal Resistance: Specifically engineered insulation prevents melting or grounding out when routed past hot furnace components

the switch is calibrated to open the circuit at 180°F to prevent heat exchanger damage and automatically reset once the temperature drops to 150°F

making it a versatile choice for variable-pressure heating applications

For technicians servicing LF009M2 or standard series 009 units

Viessmann 7819967 Sensor 322055-301 the S1-331-03009-000 is the directThe Viessmann 7819967 Sensor is a critical NTC thermistor engineered for precise temperature monitoring in Vitodens 200 W and Vitodens 100 W series condensing boilers. This dual purpose component functions as either Sensor #3 for boiler water temperature or Sensor #5 for Domestic Hot Water (DHW) tank monitoring. Designed to provide high accuracy resistance feedback to the Vitotronic control platform, it ensures the burner modulates correctly based on