Siemens (HI121) Thermal fire detector

The Siemens HI121 thermal detector is a conventional heat detector with a fixed 135°F (57°C) alarm temperature. It protects areas where smoke detection would cause nuisance alarms. For example, dusty or steamy spaces suit heat detection better.

First, the HI121 monitors ambient temperature with a single state-of-the-art thermal sensor. Then, when the air reaches 135°F, the detector signals an alarm to the fire alarm control panel. In addition, a built-in three-color LED shows status at a glance. Green flashes mean normal supervision. However, yellow indicates trouble, and red indicates alarm.

Furthermore, the HI121 supports magnet testing with the Siemens TM121 test magnet. As a result, technicians can verify wiring and panel connection without a heat gun. This saves time during installation and annual inspections.

Key Features of the Siemens HI121 Thermal Detector

• Fixed-temperature heat detection with a 135°F (57°C) alarm point
• Magnet-test feature — no heat gun required for functional testing
• Three-color LED (green/yellow/red) for local status indication
• Optional remote LED indicators (RLC-11, RLW-11, RSAC-11, RSAW-11)
• Suitable for open-area protection and direct in-duct application (0–4,000 ft/min air velocity)
• UL 521 Listed and ULC S530 Listed; FM and CSFM Approved

Specifications

• Siemens part number: S54372-F3-A1
• Operating voltage: 16–27 VDC
• Supervisory current: 100 µA
• Alarm current: 50 mA
• Alarm temperature: 135°F (57°C)
• Operating temperature: 32°F to 100°F (0°C to 38°C)
• Humidity: 0–95% non-condensing
• Start-up time: 30 seconds maximum

Compatibility

The HI121 is a conventional detection device in the Siemens 121-series. It mounts on the Siemens DB-11 or DB-11E detector base. For Canadian installations, use the ULC-listed DB-11C base. Also, the HI121 can connect to addressable Siemens systems through the HZM remote conventional zone module. Therefore, it fits both conventional zones and mixed intelligent systems.

For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com