Detectors
Replacing Siemens detectors: types, successors and bases
Which Siemens detectors manufactured since 2000 must be replaced, what is still available, which detector replaces older types and when a new base is needed – with the manufacturers’ order numbers.
Detector age
How old is the detector – how long has it been in operation?
- Siemens: Rating plate with type, order number and date of manufacture or serial number. With Sinteso and Cerberus PRO systems, detector data can be retrieved via the panel’s operating unit or engineering tool.
- Logbook and reports (decisive): The operating time counts from the commissioning of the detector. The date is recorded in the logbook, in the commissioning or acceptance report or in the last replacement report. This gives the years and months in operation.
- Type plate on the detector: The label (usually on the underside or side of the detector, visible after twisting it out of the base) shows the type, serial number and date of manufacture or a date code (e.g. year/calendar week). If no commissioning date is documented, we take the cautious approach of calculating from the date of manufacture.
- Reading out via the panel: With many addressable loop detectors, detector data such as serial number, date of manufacture, degree of contamination and – depending on the system and software version – operating hours can be retrieved via the panel’s operating unit or programming software. We do this during the survey using your programming file.
This determines the replacement interval under DIN 14675: as a rule 5 years, or 8 years for detectors with contamination compensation and testing in accordance with the manufacturer’s specifications – details under Deadlines & standards. Send us a photo of the type plate and we will determine the age for you.
Identify
Which Siemens detector is installed at your site?
Siemens fire detectors (formerly Cerberus) since 2000 come from these families: AlgoRex (types DO11…, DOT11…, DT11…), SIGMALOOP/SIGMASYS (SDF…, SDT…), Sinteso (FDO241, FDT241, FDOOT241…, panels FC20/FS20) and Cerberus PRO (OP720, OH720, HI720, OOH740, panels FC720/FS720). The type designation is printed on the detector, the order number (S5431…, A5Q…) on the rating plate.
Images: Siemens. Examples shown; housing colour and labelling may vary by type.
No longer available
AlgoRex and SIGMALOOP: replacing detectors with Sinteso multi-protocol detectors
For systems with AlgoRex– or SIGMALOOP-based detectors, Siemens offers Sinteso multi-protocol detectors. They are fitted onto the existing base using a pre-wired base adapter – according to Siemens without new wiring, simply a detector replacement.
AlgoRex interactive → FDOOT241-A5 with base adapter FDB251
| Image | Old detector | Old type | Available? | Alternative detector | New base? |
|---|---|---|---|---|---|
| Optical smoke detector AlgoRex interactive | DO1151A | no – discontinued | FDOOT241-A5¹ | Base adapter FDB251 (S54319-F28-A1) |
| Optical smoke detector AlgoRex interactive | DO1152A | no – discontinued | FDOOT241-A5¹ | Base adapter FDB251 (S54319-F28-A1) |
| Optical smoke detector AlgoRex interactive | DO1153A | no – discontinued | FDOOT241-A5¹ | Base adapter FDB251 (S54319-F28-A1) |
| Multi-criteria detector AlgoRex interactive | DOT1151A | no – discontinued | FDOOT241-A5¹ | Base adapter FDB251 (S54319-F28-A1) |
| Multi-criteria detector AlgoRex interactive | DOT1152A | no – discontinued | FDOOT241-A5¹ | Base adapter FDB251 (S54319-F28-A1) |
| Heat detector AlgoRex interactive | DT1152A | no – discontinued | FDOOT241-A5¹ or heat detector according to concept | Base adapter FDB251 (S54319-F28-A1) |
AlgoRex collective → FDOOT241-A9 with base adapter FDB299
| Image | Old detector | Old type | Available? | Alternative detector | New base? |
|---|---|---|---|---|---|
| Optical smoke detector AlgoRex collective | DO1131A | no – discontinued | FDOOT241-A9 (S54310-F11-A1) | Base adapter FDB299 (S54319-F14-A1) |
| Multi-criteria detector AlgoRex collective | DOT1131A | no – discontinued | FDOOT241-A9 (S54310-F11-A1) | Base adapter FDB299 (S54319-F14-A1) |
| Heat detector AlgoRex collective | DT1131A | no – discontinued | FDOOT241-A9 (S54310-F11-A1) or heat detector according to concept | Base adapter FDB299 (S54319-F14-A1) |
| Heat detector AlgoRex collective | DT1132A | no – discontinued | FDOOT241-A9 (S54310-F11-A1) or heat detector according to concept | Base adapter FDB299 (S54319-F14-A1) |
SIGMALOOP / SIGMASYS → FDOOT241-A3 with base adapter FDB241
| Image | Old detector | Old type | Available? | Alternative detector | New base? |
|---|---|---|---|---|---|
| Smoke detector SIGMALOOP | SDF1200 | no – discontinued | FDOOT241-A3 (S54310-F10-A1) | Base adapter FDB241 (S54319-F13-A1) |
| Smoke detector SIGMALOOP | SDF2200 | no – discontinued | FDOOT241-A3 (S54310-F10-A1) | Base adapter FDB241 (S54319-F13-A1) |
| Smoke detector SIGMALOOP | SDF3100 | no – discontinued | FDOOT241-A3 (S54310-F10-A1) | Base adapter FDB241 (S54319-F13-A1) |
| Heat detector SIGMALOOP | SDT2100 | no – discontinued | FDOOT241-A3 (S54310-F10-A1) or heat detector according to concept | Base adapter FDB241 (S54319-F13-A1) |
Assignment of detector family → multi-protocol detector and base adapter according to the Siemens technical manual FDOOT241-9 and the Siemens HIT catalogue. ¹ Order number of the FDOOT241-A5 on request. According to Siemens, heat detectors are also replaced by the multi-protocol multi-sensor detector; whether a pure heat detector is required (e.g. in kitchens) is agreed on the basis of the fire protection concept.
Current series
Sinteso and Cerberus PRO: same detector, same base
These Siemens detectors are available. When replaced on schedule, the detector is exchanged for the same type; the existing base remains.
| Image | Detectors | Item no. | Available? | Replace with | New base? |
|---|---|---|---|---|---|
| Multi-sensor fire detector Sinteso FDOOT241-A (ASA, FDnet) | S54310-F13-A1 | yes | same type | no – base FDB221 remains |
| Multi-sensor fire detector Sinteso FDOOT241-A9 (multi-protocol) | S54310-F11-A1 | yes | same type | no |
| Multi-sensor fire detector Sinteso FDOOT241-A3 (SIGMA/A+) | S54310-F10-A1 | yes | same type | no |
| Multi-sensor fire detector Sinteso FDOOT241-9 (multi-protocol, older version) | A5Q00004813 | on request | same type or FDOOT241-A9 | no |
| Smoke detector Sinteso FDO241 | A5Q00004811 | on request | same type | no |
| Heat detector Sinteso FDT241 | A5Q00004812 | on request | same type | no |
| Optical smoke detector Cerberus PRO OP720 | S54310-F1-A1 | yes | same type | no – DB721/DB722 remains |
| Multi-sensor smoke detector Cerberus PRO OH720 | S54310-F2-A1 | yes | same type | no |
| Heat detector Cerberus PRO HI720 (fixed-temperature + rate-of-rise) | S54310-F4-A1 | yes | same type | no |
| Heat detector Cerberus PRO HI722 (fixed-temperature) | S54310-F3-A1 | yes | same type | no |
| Multi-sensor smoke detector Cerberus PRO OOH740, ASA | S54320-F7-A3 | yes | same type | no |
“On request”: we clarify delivery status or successors with Siemens. Further variants (e.g. OOHC740 with CO, Ex versions) on request.
Bases
Siemens bases and base adapters: when a new base is needed
With Sinteso and Cerberus PRO, the base remains when the detector is replaced. For AlgoRex and SIGMALOOP, there are pre-wired base adapters that are fitted onto the existing base. According to Siemens, on CZ10 panels the bases Z7x and Z9x must be replaced with the base FDB201.
| Image | Base / adapter | Item no. | Suitable for | Note |
|---|---|---|---|---|
| Detector base DB721 with loop-through contact | S54319-F11-A1 | Cerberus PRO (OP720, OH720, HI720, HI722) | remains during replacement |
| Detector base DB722 | S54319-F19-A1 | Cerberus PRO | remains during replacement |
| Base attachment BA720 | S54319-F20-A1 | Cerberus PRO | Accessories |
| Detector base FDB221 (standard) | on request | Sinteso S-LINE | remains during replacement |
| Base adapter FDB251 (AlgoRex interactive) | S54319-F28-A1 | FDOOT241-A5 on AlgoRex interactive base | instead of base replacement |
| Base adapter FDB299 (AlgoRex collective / SIGMACON) | S54319-F14-A1 | FDOOT241-A9 on AlgoRex collective base | instead of base replacement |
| Base adapter FDB241 (SIGMA/A+) | S54319-F13-A1 | FDOOT241-A3 on SIGMALOOP base | instead of base replacement |
| Base adapter FDB281 (MS8/PMT) | A5Q00004929 | FDOOT241-8 | instead of base replacement |
Special detectors
Siemens: wireless, Ex, ventilation duct and linear detectors
For special applications, Siemens offers wireless, Ex, duct, linear beam and flame detectors in the Sinteso system (FDnet). We will provide order numbers with our quote.
| Image | Detectors | Item no. | Available? | Replace with | Note |
|---|---|---|---|---|---|
 | Wireless fire detector optical/thermal FDOOT271 (SWING wireless system, MESH), battery-powered (EN 54-5/-7/-25) | on request (at SONAX-ALARM: 230001) | yes | same type; battery pack according to manufacturer’s specifications | wireless base FDB271 remains; gateway FDCW241 |
 | Dual-optical Ex smoke detector OOH740-A9-Ex for zones 0, 1 and 2, via safety barrier SB3 (VdS G 214047) | on request (at SONAX-ALARM: 230060) | yes – according to SONAX discontinued Q4/2026 | ask Siemens for successor | Ex barrier remains |
| – | Linear beam smoke detector FDL241-9 (EN 54-12) | on request | yes | same type | – |
| – | Flame detector FDF241-9 (EN 54-10) | on request | yes | same type | – |
| – | Aspirating smoke detector FDA221 / FDA241 (EN 54-20) | on request | yes | detector according to manufacturer’s specifications | pipe network remains |
| – | Ventilation duct sampling housing FDBZ492 for Sinteso smoke detectors | on request | yes | inserted detector according to replacement interval | housing remains |
Types according to the Siemens system overview Sinteso FDnet (10969D) and the SONAX-ALARM product catalogue 2026 (structurally identical wireless and Ex detectors).
Important
Before ordering
- Check the panel: Whether Sinteso or Cerberus PRO detectors can be operated on your panel (AlgoRex, SIGMASYS, FC20/FS20, FC720/FS720) depends on the panel, protocol and software version. We check this using your detector list and programming file.
- Replacement interval: Smoke and multi-sensor detectors after 5 years at the latest, or after 8 years with automatic contamination compensation and testing in accordance with the manufacturer’s specifications – details under Deadlines & standards.
- Change of detector series: New bases, different detector types or a changed number of detectors may constitute a significant modification – see expert inspection and fire brigade.
- EN 54 tested (as of 19.10.2026): All Siemens detectors listed as available (Sinteso, Cerberus PRO) are certified to EN 54-5 or EN 54-7, and detectors with isolator additionally to EN 54-17. The detectors that are no longer available were approved under the EN 54 or VdS rules in force when they were introduced; since 2008, CE marking to EN 54 has been mandatory for new detectors – which is why we only name currently certified types as replacements.
- Installation by a specialist company only: Replacement and repair of detectors in fire alarm systems required under building law are part of maintenance and are reserved for a specialist company certified to DIN 14675 – even if you only buy the detectors from us. Details under Legal situation.
- Order numbers are Siemens order numbers (sources: Siemens HIT catalogue, Siemens data sheets and technical manual FDOOT241-9, last updated: 18.10.2026).
- Image credits and trademarks: Product images © Siemens. The images serve solely to identify the detectors. Brand and product names are the property of their respective owners. Further details in the Legal notice.
Not sure which detector is installed at your site?
Send us your detector list or a photo of the type plate. We will name the suitable replacement and tell you whether new bases are needed.