Siemens HI121 (S54372-F3-A1) — conventional fixed-temperature thermal heat detector, 135°F alarm point.
Heat detection is specified where smoke detection would nuisance-alarm: boiler rooms, kitchens, loading docks, attics and dusty or steamy spaces. The HI121 uses a single thermal sensor for uniform response and adds a magnet-test feature, so a technician can prove wiring and panel connection with the TM121 test magnet instead of carrying a heat gun up a ladder. A three-color LED reports status locally.
- Alarm temperature: 135°F (57°C), fixed temperature
- 16–27 VDC; ripple 3 V peak to peak
- Supervisory current 100 µA; alarm current 50 mA
- Start-up time 30 seconds max
- 32°F to 100°F (0°C to 38°C), 0–95% non-condensing
- Air velocity 0–4000 ft/min, open area or in-duct
- Bases: DB-11, DB-11E; DB-11C for ULC
- UL 521, ULC S530, FM and CSFM approved
This is a conventional detector for an initiating device circuit, not an addressable head. The base is ordered separately.
