FDM-1 is a standard-sized dual monitor module used to monitor and supervise two independent two-wire Style B (Class B) dry-contact initiating device circuits (IDCs) at two separate, consecutive addresses in intelligent, two-wire systems.
The SD-651 is designed to meet the performance criteria designated by UL. Its sensing chambers are sealed against back pressure air flow, dirt, and insects.
The Thermotech 302 Series rate-anticipation heat detec- tors operate within a controlled range of two to three de- grees of their set points, regardless of the speed or rate of temperature rise.