We cannot confirm that the Siemens HFP-11 is discontinued: we found no Siemens document that says so. The current Siemens detectors for the same DB-11 base and FireFinder XLS panels are the OP921, OH921, OOH941 and OOHC941, and their addresses are programmed with the same DPU.
Is the Siemens HFP-11 discontinued?
Not according to any Siemens document we could find, so we do not label it that way. Here is what we checked on Siemens' own document portal (sid.siemens.com) in October 2026:
- The HFP-11 / HFPT-11 installation instructions (P/N 315-033290-11) are still published.
- The current data sheets for the OP921, OH921, OOH941, OOHC941 and FDO421 all name the HFP-11 and HFPT-11 as H-series devices that can sit on the same circuit. That is a statement of coexistence. None of those data sheets says the newer model replaces the HFP-11.
- A portal search returned no end-of-life notice for the HFP-11. It also returned no current HFP-11 data sheet, which proves nothing by itself but is worth knowing when you need a submittal.
To confirm the status, ask your Siemens Smart Infrastructure branch or Siemens fire dealer for the lifecycle status of part number 500-033290 and the recommended successor for your panel and its firmware. We continue to list the HFP-11 for service work on existing systems.
Which current Siemens detector fits the same base and panel?
For FireFinder XLS, the OP921, OH921, OOH941 and OOHC941 data sheets all list FireFinder XLS and XLSV among their compatible panels and the DB-11 among their bases. The OH921 is the closest in function to the HFP-11, because it also combines a photoelectric chamber with a thermal sensor.
| Model | Sensing | Panels named on the Siemens data sheet | Bases |
|---|---|---|---|
| HFP-11 (500-033290) | FirePrint photoelectric plus thermal | FireFinder XLS and FS-250 (installation instructions) | DB-11; DB-HR relay base |
| OP921 (S54320-F4-A2) | Photoelectric smoke | FireFinder XLS, XLSV; Cerberus PRO Modular, FC901, FC922, FC924, FV922, FV924 | DB-11, DB-11E, DB2-HR |
| OH921 (S54320-F6-A2) | Photoelectric plus heat; 135°F fixed or 15°F per minute rate-of-rise | FireFinder XLS, XLSV; Cerberus PRO Modular and FC9-series | DB-11, DB-11E, DB2-HR |
| OOH941 (S54320-F7-A2) | Dual optical plus thermal, multi-criteria (ASAtechnology) | FireFinder XLS, XLSV; Cerberus PRO Modular, FC9 and FV9 series | DB-11, DB-11E, DB2-HR |
| OOHC941 (S54320-F8-A2) | Dual optical, thermal and CO; 10-year CO sensor life | FireFinder XLS, XLSV; Cerberus PRO panels | DB-11 series |
| FDO421 (S54320-F4-A1) | Photoelectric smoke | FireFinder XLS, XLSV; Desigo Fire Safety Modular, FC2005, FC2025, FC2050, FV2025, FV2050 | DB-11, DB-11E, DB2-HR |
Three limits to keep in view:
- FS-250. The HFP-11 instructions cover FireFinder XLS and FS-250. None of the 9xx-series or FDO421 data sheets names the FS-250, so do not assume a 9xx head is listed on that panel. Ask Siemens.
- MXL. The FP-11 is the FirePrint detector whose data sheet covers FireFinder XLS and MXL panels. The 9xx-series data sheets do not name MXL.
- Panel configuration. A different model is a different device type to the panel. On FireFinder XLS the detector's application is set with the Zeus programming tool, so expect a configuration change by whoever maintains the panel program. This point is our reading of the instructions, not a Siemens statement about a specific swap.
OP921 vs OOH941 vs OOHC941 vs FDO421: what is the difference?
The OP921 is a single-sensor photoelectric detector. The OOH941 adds a second optical path and thermal sensing and can be programmed as a high-sensitivity detector. The OOHC941 adds a carbon monoxide sensor to that. The FDO421 is the photoelectric detector catalogued for the Desigo Fire Safety panel line, where the OP921 is catalogued for Cerberus PRO. All are listed to UL 268 7th edition and all carry FireFinder XLS on their data sheets. Order the model your panel's listing documents call for; do not substitute OP921 and FDO421 for each other on the strength of similar specifications.
Does the replacement fit the DB-11 base already installed?
Yes for the plain bases. Siemens' base data sheet states that the DB-11 and DB-11E function with the OH921, OP921, OOH941, OOHC941 and HI921, and the HFP-11 instructions call for the DB-11.
Relay and audible bases need a second look:
- The DB2-HR is a redesign of the DB-HR. Siemens describes it as backwards compatible with H-series intelligent detectors, and it needs a 4 inch square, double-gang box. The older DB-HR is described only as the relay base for H-series detectors, so a 9xx head on an existing DB-HR is a question for Siemens.
- The OP921 data sheet lists the ABHW-4 series audible bases as its compatible audible bases. If the HFP-11 sits on an ADBH-11 audible base, check that base against the new detector's data sheet before ordering heads only.
Do I need a DPU to program the replacement?
You need access to one. Siemens detectors in these families have no dials or switches; the address is written electronically.
- The HFP-11 instructions say to program the address, a unique number from 001 to 252, with the Model DPU.
- The OP921, OH921, OOH941, OOHC941 and FDO421 data sheets each list the DPU (called 8720 in some Cerberus PRO literature) as the compatible programmer and tester.
What the DPU does, per its data sheet and user guide: it writes the address into the device's non-volatile memory, then tests the device before installation. Detectors drop into a DB-11 base built into the unit; other devices connect by cable. It can also run a loop test and find ground faults before the circuit is connected to the panel, on AC power only. That loop test is not available in MXL mode.
The user guide adds a setting to get right: choose the XLS/FC system setting for Cerberus PRO, Desigo and FC/FV panels, and the MXL setting for devices on a FireFinder XLS MLC loop driver. If you replace one or two heads a year, a service company with a DPU is the practical route. If you maintain Siemens systems, the programmer is in our programmer collection.
What about the HFPT-11 and heat-only locations?
The HFPT-11 is the thermal-only FirePrint detector covered by the same installation instructions as the HFP-11. The current heat detector on the DB-11 base is the HI921. As with the smoke heads, Siemens documents the two generations side by side and does not publish a cross-reference that we could find.
What to order
For service on an existing FireFinder XLS loop, the like-for-like part is the HFP-11. For a change to the current generation, pick from the table, confirm the panel listing and plan the programming. All of these are in the Siemens collection. For a list of heads, bases and a programmer, request a quote.
Compatibility must be confirmed against the control panel's listing documents, and the installation must follow NFPA 72 and the local AHJ.
Sources
- Siemens, HFP-11 / HFPT-11 FirePrint Detector Installation Instructions, P/N 315-033290-11 (A6V10239116): sid.siemens.com
- Siemens, OP921 Photoelectric Smoke Detector, Data Sheet 9902, Rev. 15, August 2024 (A6V10343336): sid.siemens.com
- Siemens, OH921 Multi-Criteria Fire Detector, Data Sheet, Rev. 18, November 2024 (A6V10337771): sid.siemens.com
- Siemens, OOH941 Multi-Criteria Fire Detector, Data Sheet, Rev. 12, March 2024 (A6V10350303): sid.siemens.com
- Siemens, OOHC941 Multi-Criteria Fire / CO Detector, Data Sheet, Rev. 11, March 2024 (A6V10350298): sid.siemens.com
- Siemens, FDO421 Photoelectric Smoke Detector, Data Sheet, Rev. 16, August 2024 (A6V10342766): sid.siemens.com
- Siemens, FP-11 Intelligent Fire Detector, Data Sheet, Rev. 3 (A6V10232953): sid.siemens.com
- Siemens, DB2-HR, DB-11 and DB-11E Detector Bases, Data Sheet 9907, Rev. 3, August 2024 (A6V10370262): cache.industry.siemens.com
- Siemens, DPU / DPU-C1 / DPU-RPT Device Programmer / Test Unit, Data Sheet 6313, Rev. 5, March 2023 (A6V10238855): sid.siemens.com
- Siemens, Device Programming Unit (DPU) User Guide (A6V10276604): sid.siemens.com