The Siemens FDO421 is a plug-in, two-wire, addressable photoelectric smoke detector. It belongs to Siemens’ Desigo Fire Safety detector family. First, light from an infrared LED scatters off smoke particles inside the sensing chamber. Then a photodiode reads that scattered light. As a result, the detector produces highly stable, accurate smoke detection.
Specifically, the Siemens FDO421 is UL 268A Listed for direct in-air duct use. In addition, it carries ULC Listing, FM approvals (#3230 and #3210), and CSFM approval (#7272-0067:0258). The Siemens part number is S54320-F4-A1.
Panel compatibility for the Siemens FDO421
The FDO421 works with Siemens Desigo Fire Safety Modular panels. In addition, it operates on FireFinder XLS, XLSV, and FC/FV20-series fire alarm control panels. Furthermore, it shares the loop with Siemens “H”-series devices on the same SLC.
For example, you can mix it with HFP-11, HFPT-11, HMS-series manual stations, HCP output-control devices, and HZM zone modules. Also, the XTRI-series and HTRI-series interface modules ride the same loop.
Sensitivity and self-testing features
Each detector is self-monitoring for sensitivity within UL Listed limits. Furthermore, internal diagnostics run every 10 seconds. As a result, no field sensitivity test is required.
The Siemens FACP selects from four pre-programmed sensitivity profiles. First, “Sensitive” suits clean spaces with few false-alarm sources. Then “Standard” is the default for office and hotel lobbies. In addition, “Robust” resists cigarette smoke and exhaust nuisance alarms. Finally, “Air-Duct” applies when the detector is used as a UL 268A-compliant direct-duct device or inside FDBZ492 / FDBZ492-HR duct housings.
Status indication and installation
A 360° tri-color LED reports detector status. Specifically, green flashes every 10 seconds for normal operation. Yellow flashes every 4 seconds to signal trouble. Then red flashes once per second during alarm. Also, the panel can disable the LED if needed.
The FDO421 mounts on DB-11 or DB-11E surface bases. Furthermore, the bases fit a 4-inch octagonal, square, or single-gang back box. In addition, an optional LK-11 locking kit prevents unauthorized removal. For Canadian projects, order the ULC-Listed DB-11C base.
The detector uses Siemens SureWire polarity-insensitive wiring. As a result, installation and debugging times drop. Also, T-tapping is allowed only on Style 4 (Class B) circuits. The DPU field programmer addresses the detector electronically — no rotary switches needed.
Technical specifications
- Input voltage range: 16-30 VDC
- Standby current: 280 µA max (average)
- Alarm current: 280 µA max
- Operating temperature: 32-120 °F (0-49 °C)
- Relative humidity: 0-95% non-condensing
- Air velocity: 0-4,000 ft/min (0-20 m/s)
- Maximum spacing: 30-ft centers (900 sq ft) per NFPA 72
- Weight: 0.317 lb (0.144 kg)
- Listings: UL 268A, ULC, FM #3230 / #3210, CSFM #7272-0067:0258, RoHS compliant
- Mounting bases: DB-11, DB-11E, DB-11C (Canada), DB2-HR (with relay)
- Duct housings: FDBZ492, FDBZ492-HR
For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com
Additional information
| Weight | 0.1 lbs |
|---|---|
| Dimensions | 4.25 × 4.25 × 1.75 in |
| Condition | New |
| Manufacturers | Siemens |
| Part Type | Photoelectric Smoke Detector |
