The Siemens HI921 heat detector is an intelligent, addressable thermal detector for Cerberus PRO and FireFinder XLS systems. It combines fixed-temperature and rate-of-rise sensing in a single device.
First, the HI921 uses a shock-resistant thermistor with microprocessor signal analysis. Then, it reports temperature data continuously to the panel. As a result, the panel can distinguish a real fire from normal temperature swings.
Seven field-selectable temperature settings
The Siemens HI921 heat detector ships with seven pre-programmed temperature profiles:
- Fixed 135 °F (57 °C)
- Fixed 145 °F (63 °C)
- Fixed 155 °F (68 °C)
- Fixed 165 °F (74 °C)
- Fixed 174 °F (79 °C)
- Rate-of-Rise 15 °F/min at fixed 135 °F
- Rate-of-Rise 15 °F/min at fixed 174 °F
In addition, the detector can be configured to report a low-temperature warning at 40 °F (4.4 °C). For example, this feature helps prevent sprinkler-pipe freezing in unheated spaces.
Tri-color status LED
A 360°, tri-color LED flashes one of three colors:
- Green every 10 s — normal supervisory operation
- Yellow every 4 s — detector needs replacement
- Red every 1 s — alarm condition
Also, each detector runs a complete self-diagnostic every 10 seconds. Therefore, technicians can verify health with a quick visual inspection.
Specifications for the Siemens HI921 heat detector
- Type: Two-wire, addressable, polarity-insensitive (SureWire™)
- Input voltage: 16–30 VDC
- Standby current: 250 µA max
- Alarm current: 410 µA max
- Operating temperature: 32–120 °F (0–49 °C) for 145/155/165/174 °F settings; 32–100 °F for the 135 °F setting
- Relative humidity: 0–95% non-condensing
- NFPA 72 spacing: 50 ft (15.24 m) centers, 2,500 sq ft (232.3 m²), per UL/ULC-S524
- Weight: 0.317 lb (144 g)
- Listings: UL 521 Listed; ULC Listed; FM #3230, #3210; CSFM #7272-0067:0258
- RoHS compliant
- Programmable via Siemens Model 8720 DPU
- Part number: S54320-F5-A2
- Source: Siemens Data Sheet 9901 (Rev 8, November 2019)
Compatible panels and bases
The HI921 works with Cerberus PRO Modular, FireFinder XLS/V, FC901, FC922, FC924, FV922, and FV924 panels. Furthermore, it mounts on Siemens DB-11, DB-11E, DB-11C (Canada), or DB2-HR relay bases. The optional LK-11 detector locking kit secures the head against unauthorized removal.
Order or get application help
Life Safety Consultants stocks the genuine Siemens HI921 heat detector for retrofit and new-build work. To order, call 1-888-557-0558. You can also email sales@lifesafetycom.com.
For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com
Additional information
| Weight | 1 lbs |
|---|---|
| Dimensions | 5 × 5 × 2 in |
| Condition | New |
| Manufacturers | Siemens |
| Part Type | Pull Station |
