Detectors
Replacing Bosch and SONAX-ALARM detectors: types, successors and bases
Which Bosch and SONAX-ALARM detectors manufactured from 2000 onwards 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?
- Bosch / SONAX-ALARM: Rating plate with type, product number and date of manufacture or date code. LSN improved detectors transmit their identification data to the control panel (FPA-5000 / AVENAR panel); read-out via the panel’s diagnostics or the programming software.
- 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 Bosch or SONAX-ALARM detector do you have installed?
The images show the current Bosch designs. SONAX-ALARM distributes Bosch’s LSN fire detectors in identical form under the Bosch type designations, but with its own item numbers. Within a series, many types look the same – what matters is the type designation on the rating plate on the detector. This also tells you the series: FAP-/FAH-…420 = Series 420 (MAGIC.SENS), FAP-/FAH-425 = AVENAR detector 4000 (LSN), FCP-/FCH-… 320 = Series 320 (conventional technology), FAP-… 520 / FCP-… 500 = flush-mounted Series 520 (LSN) and 500 (conventional technology). On the Series 425, a coloured ring around the LED indicates the type: no ring = O, black = OT, red = T, 2 × yellow = DOTC, 2 × pastel blue = DOTCO.
Images: SONAX-ALARM fire detection product catalogue 2026 (identical Bosch detectors). Examples shown; housing colour and labelling may vary by type.
No longer available
Bosch Series 420 (MAGIC.SENS): replace detector, base remains
The automatic detectors of the BoschSeries 420 (LSN improved) have been discontinued. The successor is the Series 425 (AVENAR detector 4000). Unlike with ESSER, the successor fits the existing standard bases MS 400 / MS 400 B / MS 420 – the base remains. The 425 detectors can also be operated on classic LSN control panels (e.g. BZ 500 LSN, UEZ 2000 LSN).
Series 420 (LSN) → AVENAR detector 4000
| Image | Old detector | Old Bosch no. | Available? | Alternative detector (Bosch no. / SONAX item no.) | New base? |
|---|---|---|---|---|---|
 | Optical smoke detector FAP-O 420 | F.01U.508.813 | no – discontinued | FAP-425-O-R (F.01U.307.726 / SONAX 230043) | no – MS 400 remains |
| Multi-sensor detector optical/thermal FAP-OT 420 | F.01U.508.815 | no – discontinued | FAP-425-OT-R (F.01U.307.728 / SONAX 230045) | no – MS 400 remains |
| Heat detector FAH-T 420 | F.01U.508.915 | no – discontinued | FAH-425-T-R (F.01U.307.732 / SONAX 230041) | no – MS 400 remains |
| Dual-optical smoke detector FAP-DO 420 | F.01U.116.032 | no – discontinued | FAP-425-DO-R (F.01U.307.729 / SONAX 230046) | no – MS 400 remains |
| Multi-sensor detector dual-optical/thermal FAP-DOT 420 | F.01U.116.033 | no – discontinued | FAP-425-DOT-R (F.01U.307.730 / SONAX 230047) | no – MS 400 remains |
| Multi-sensor detector optical/thermal/chemical FAP-OTC 420 | F.01U.508.816 | no – discontinued | FAP-425-DOTCO-R (F.01U.395.473 / SONAX 230049)¹ | no – MS 400 remains |
| Multi-sensor detector dual-optical/thermal/chemical FAP-DOTC 420 | F.01U.116.034 | no – discontinued | FAP-425-DOTCO-R (F.01U.395.473 / SONAX 230049)¹ | no – MS 400 remains |
| Optical smoke detector FAP-O 420 KKW | F.01U.508.687 | no – discontinued | Solution on request² | on request |
| Heat detector FAH-T 420 KKW | F.01U.508.686 | no – discontinued | Solution on request² | on request |
| – | Optical smoke detector MAGIC.SENS O 400 E LSN (LSN classic) | 4.998.121.032 | no – discontinued | FAP-425-O-R (F.01U.307.726 / SONAX 230043)⁴ | no – MS 400 remains |
| – | Multi-sensor detector optical/thermal MAGIC.SENS OT 400 E LSN | 4.998.130.602 | no – discontinued | FAP-425-OT-R (F.01U.307.728 / SONAX 230045)⁴ | no – MS 400 remains |
| – | Heat detector MAGIC.SENS T 400 E LSN | 4.998.130.603 | no – discontinued | FAH-425-T-R (F.01U.307.732 / SONAX 230041)⁴ | no – MS 400 remains |
| – | Multi-sensor detector optical/chemical MAGIC.SENS OC 410 LSN | 4.998.101.152 | no – discontinued | FAP-425-DOTCO-R (F.01U.395.473 / SONAX 230049)⁴ | no – MS 400 remains |
| – | Multi-sensor detector optical/thermal/chemical MAGIC.SENS OTC 410 LSN | 4.998.101.151 | no – discontinued | FAP-425-DOTCO-R (F.01U.395.473 / SONAX 230049)⁴ | no – MS 400 remains |
| – | Optical smoke detector MAGIC.SENS O 300 (conventional technology) | 4.998.117.239 | no – discontinued | FCP-O 320 (F.01U.026.293 / SONAX 230358) | no – MS 400 remains |
| – | Multi-sensor detector optical/thermal MAGIC.SENS OT 300 (conventional technology) | 4.998.025.351 | no – discontinued | FCP-OT 320 (F.01U.026.295 / SONAX 230360) | no – MS 400 remains |
| – | Heat detector MAGIC.SENS T 300 (conventional technology) | 4.998.025.354 | no – discontinued | FCH-T 320 (F.01U.026.291 / SONAX 230359) | no – MS 400 remains |
| – | Heat detector MAGIC.SENS T 300 / FSA (hold-open systems) | 4.998.107.056 | no – discontinued | FCH-T 320 – check approval for hold-open system | no – MS 400 remains |
| – | Multi-sensor detector optical/chemical MAGIC.SENS OC 310 (conventional technology) | 4.998.101.153 | no – discontinued | FCP-OC 320 (F.01U.026.292 / SONAX 230361) | no – MS 400 remains |
| – | MAGIC.SENS KKW versions O / OT / T 400 LSN KKW | 4.998.131.148 / …147 / …146 | no – discontinued | Solution on request² | on request |
¹ The FAP-425-DOTCO-R requires an AVENAR panel 2000/8000 or a SONAX FSO 3000/4000 with firmware 4.3 or later. On older panels, the FAP-425-DOTC-R (Bosch F.01U.307.731) replaces the detectors with CO sensor. ² For detectors in nuclear power plants (KKW), we coordinate the replacement with the manufacturer. Older delivery versions of the 425 series still carry part numbers F.01U.279.xxx / F.01U.280.xxx – these are technically identical detectors.
⁴ First-generation MAGIC.SENS detectors (Bosch product information 2003) were operated on LSN classic panels (e.g. BZ 500, UEZ 2000, UGM 2020) in the MS 400 base. We check from the programming file whether the LSN improved successors can be operated on your panel (classic mode, software version) – if necessary, the panel must be modernised.
Current series
AVENAR, Series 320, 520 and 500: same detector, same base
The following detectors are still available. When replaced in accordance with the deadline, the detector is exchanged for the same type and the existing base remains. The Bosch original and the SONAX-ALARM version are identical in construction.
| Image | Detectors | Item no. (Bosch / SONAX) | Available? | Replace with | New base? |
|---|---|---|---|---|---|
| Optical smoke detector AVENAR FAP-425-O-R | F.01U.307.726 / SONAX 230043 | yes | same type | no – MS 400 remains |
| Optical smoke detector AVENAR FAP-425-O (without rotary switch) | F.01U.307.725 | yes | same type | no |
| Multi-sensor detector optical/thermal AVENAR FAP-425-OT-R | F.01U.307.728 / SONAX 230045 | yes | same type | no |
| Multi-sensor detector optical/thermal AVENAR FAP-425-OT (without rotary switch) | F.01U.307.727 | yes | same type | no |
| Heat detector AVENAR FAH-425-T-R | F.01U.307.732 / SONAX 230041 | yes | same type | no |
 | Dual-optical smoke detector AVENAR FAP-425-DO-R | F.01U.307.729 / SONAX 230046 | yes | same type | no |
 | Multi-sensor detector dual-optical/thermal AVENAR FAP-425-DOT-R | F.01U.307.730 / SONAX 230047 | yes | same type | no |
| Multi-sensor detector dual-optical/thermal/CO AVENAR FAP-425-DOTCO-R | F.01U.395.473 / SONAX 230049 | yes | same type³ | no |
| Multi-sensor detector dual-optical/thermal/chemical AVENAR FAP-425-DOTC-R | F.01U.307.731 | yes | same type³ | no |
| Heat detector Series 320 FCH-T 320 (conventional technology) | F.01U.026.291 / SONAX 230359 | yes | same type | no – MS 400 remains |
| Optical smoke detector Series 320 FCP-O 320 | F.01U.026.293 / SONAX 230358 | yes | same type | no |
| Multi-sensor detector optical/thermal Series 320 FCP-OT 320 | F.01U.026.295 / SONAX 230360 | yes | same type | no |
 | Multi-sensor detector optical/chemical Series 320 FCP-OC 320 | F.01U.026.292 / SONAX 230361 | yes | same type | no |
| Flush-mounted smoke detector Series 520 FAP-O 520, white (LSN) | F.01U.510.149 / SONAX 230284 | yes | same type | no – FAA-500 remains |
| Flush-mounted smoke detector Series 520 FAP-O 520-P, transparent (LSN) | F.01U.510.161 / SONAX 230286 | yes | same type | no – FAA-500 remains |
| Flush-mounted detector optical/chemical FAP-OC 520, white (LSN) | F.01U.510.151 / SONAX 230285 | yes | same type | no – FAA-500 remains |
| Flush-mounted detector optical/chemical FAP-OC 520-P, transparent (LSN) | F.01U.510.162 / SONAX 230287 | yes | same type | no – FAA-500 remains |
| Flush-mounted smoke detector Series 500 FCP-O 500, white (conventional technology) | SONAX 230342 | yes | same type | no – FCA-500 remains |
| Flush-mounted smoke detector Series 500 FCP-O 500-P, transparent (conventional technology) | SONAX 230343 | yes | same type | no – FCA-500 remains |
| Flush-mounted detector optical/chemical FCP-OC 500, white (conventional technology) | SONAX 230344 | yes | same type | no – FCA-500 remains |
| Flush-mounted detector optical/chemical FCP-OC 500-P, transparent (conventional technology) | SONAX 230345 | yes | same type | no – FCA-500 remains |
³ The CO sensor is switched off automatically after its maximum operating time; the detector then only works as an OT or DOT detector – replacement is advisable at that point. SONAX-ALARM does not list the FAP-425-O, FAP-425-OT and FAP-425-DOTC-R in its 2026 catalogue; they are available from Bosch.
Bases
When does a Bosch or SONAX detector need a new base?
With Bosch and SONAX-ALARM, a new base is usually not required: the 320, 420 and 425 series use the same standard base MS 400. A base replacement is only necessary for relay bases on older panels or when changing to the flush-mounted 520/500 series.
| Image | Bases | Item no. (Bosch / SONAX) | Suitable for | Note |
|---|---|---|---|---|
| Detector base MS 400 | 4.998.021.535 / SONAX 170037 | Series 320, 420, 425 | remains during replacement |
| Detector base MS 400 B (with Bosch logo) | F.01U.215.139 | Series 320, 420, 425 | remains during replacement |
| Detector base with relay FAA-MSR 420 (SONAX: MSR 420) | F.01U.508.658 / SONAX 230379 | Series 420, 425 | only on LSN improved panels (FPA-5000, FPA-1200 or SONAX FSO 3000/4000); solution on request for older LSN classic panels |
 | Detector base with relay MSR 320 | SONAX 230145 | Series 320 | Connection to conventional intruder alarm control panels |
 | Detector base FAA-500 (LSN) | SONAX 230304 | Series 520 | FSO 3000/4000 only (according to SONAX); additionally cavity wall box FAA-500-BB (SONAX 230306) or surface-mounting box FAA-500-SB-H (F.01U.510.166 / SONAX 230375) |
| Detector base FAA-500 with relay (LSN) | SONAX 230377 | Series 520 | FSO 3000/4000 only (according to SONAX); additionally cavity wall box FAA-500-BB (SONAX 230306) or surface-mounting box FAA-500-SB-H (F.01U.510.166 / SONAX 230375) |
| Detector base FCA-500 EU (GLT) | SONAX 230303 | Series 500 | with alarm and fault relays |
| Detector base FCA-500-E EU (GLT) | SONAX 230378 | Series 500 | with connection for end-of-line resistor (last detector on a spur line) |
The flush-mounted 520/500 series do not fit into the MS 400 – changing from Series 320/420/425 to 520/500 always means new bases and mounting boxes.
Special detectors
SONAX-ALARM / Bosch: wireless, Ex, duct and linear detectors
In addition to point-type detectors, SONAX-ALARM supplies special detectors for wireless applications, hazardous (Ex) areas, ventilation ducts and large halls. The replacement and inspection intervals under DIN 14675 and the manufacturer’s specifications also apply to them.
| Image | Detectors | Item no. | Available? | Replace with | Note |
|---|---|---|---|---|---|
 | Wireless fire detector optical/thermal FDOOT271-O, battery-operated (approx. 3 years), 433/868 MHz (EN 54-5/-7/-25, VdS G 216094) | SONAX 230001 | yes | same type; battery pack 230005 as specified by the manufacturer | Base FDB271 (SONAX 230002) remains |
 | Dual-optical smoke detector for Ex zones 0, 1 and 2 OOH740-A9-EX, via safety barrier SB3 with DCA 1192 (VdS G 214047) | SONAX 230060 | yes – according to SONAX discontinued Q4/2026 | Ask SONAX about the successor | Ex barrier remains |
 | Duct detector (housing) FAD-420-HS-EN with integrated detector FAD-425-O-R, LSN (EN 54-27, VdS G 211088) | SONAX 230307 | yes | integrated detector FAD-425-O-R | Housing and sampling tube remain |
 | Linear beam smoke detector FRAY-ONE, 5–50 m (up to 120 m with extension kit FRAY5000-LR-KIT 230021), motorised self-alignment (EN 54-12, VdS G 218070) | SONAX 230020 | yes | same type | Prisms and bracket FRAY5000-BR (230022) remain |
 | Linear beam smoke detector Firebeam Blue, 7–160 m, operated via Bluetooth app (EN 54-12, VdS G 221060) | SONAX 230064 | yes | same type | Reflectors remain |
Information according to the SONAX-ALARM product catalogue Brandmeldetechnik 2026 (as of 09/2026). Linear beam smoke detectors are not replaced according to deadlines; instead they are inspected as specified by the manufacturer and repaired if soiled or defective.
Important
Before ordering
- Check the panel: Whether AVENAR detectors (Series 425) or detectors of Series 320/520/500 can be operated on your fire alarm control panel depends on the panel, the LSN version and the programming. 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): According to the Bosch data sheets, all AVENAR, 320, 500 and 520 detectors listed as available are certified to EN 54-5 or EN 54-7 (detectors with CO sensor additionally to EN 54-26/-29/-30, depending on type). The detectors that are no longer available were approved under the EN 54 or VdS rules applicable when they were introduced; since 2008, CE marking according to EN 54 has been mandatory for new detectors – which is why we only list 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 Bosch part numbers F.01U… or 4.998… (source: Bosch data sheets and Bosch product catalogue) and SONAX-ALARM article numbers (source: SONAX-ALARM product catalogue Brandmeldetechnik 2026), last updated: 18.10.2026.
- Image credits and trademarks: Product images © Bosch Building Technologies or SONAX-ALARM (price and product catalogue 09/2026). 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.