B b sensors con sensw btf dew formation probe for sensor switching module b b sensors con sensw btf this dew formation probe is designed to be used with the sensor switching module 156503 17 30 the combined probe consists of two single sensors that work together to produce a probe that gives reliable switching behaviour making it suitable for critical applications e g cool ceilings br br the first sensor is a resistive dew sensor in thick film technology that reacts to high relati