Heat detector for use in damp areas. The detector gives alarm when reaching a fixed alarm limit, 56 oC if the temperature increases slowly. A rapid increase in temperature may cause alarm at a lower temperature. For use in hazardous areas zone 1 or zone 2. To be connected via the Autronica barrier BZ-20. Often used in areas where smoke detectors are not to be used due to the false alarm problem. The detector comprises a built-in alarm indicator (LED). The detector can be connected to an analogue addressable system by means of interface unit.