The model number suffix “-2”, indicates that the detector is a double circuit with two (2) sets of Normally Open (N/O) contacts. The second set of N/O contacts are used to activate a local ancillary function that includes elevator recall, release of magnetically-held doors, local signal operation, local annunciation, etc. In many cases this set of contacts will be connected to a controlling relay that is used to switch heavier voltages. The “CF” series detectors are installed in areas where rapid increases in ceiling temperature are expected. Such locations include boiler rooms, industrial kitchens, commercial laundry rooms, janitor closets, change rooms with shower facilities, and saunas.