This heat sensor is designed for detect heat,it adopt SMT Manufacturing Process and contains  highSensitive sensor,when the temperature reached +65 degree,it will give off alarm.

After installation, the detector will be in working status when electrified. On working status, the indicator LED will flash about once per minute.
When the detector sense the temperature is higher than the preset temperature, it will ring loudly pulse alarm sound. And the red indicator LED will flash rapidly. It will not stop till the circumstance temperature is lower than the preset temperature.