Siemens FDBZ492 — air duct monitoring housing, S54319-B22-A1, supplied without relays and without a detector head.
It mounts to an HVAC duct and draws a cross-sectional air sample in through an inlet tube and out a short outlet tube, so smoke that would stratify past a spot detector still reaches the chamber. Data sheet 6156 names the minimum hardware: one housing, one sampling tube, one detector.
- Two-wire housing taking addressable or conventional Siemens detectors, no relays
- Listed detectors: OP121, PE-11, PE-11C, FP-11, HFP-11, HFPO-11, SFP-11, SFPO-11, FDO421
- Air velocity 100 to 4,000 ft. per minute
- Duct temperature is set by the detector fitted: 32 to 100 °F with the PE, FP, HFP or SFP heads, 32 to 120 °F with OP121 or FDO421
- Clear cover with smoke test port, four captive thumb screws
- Two 3/4 in. knockouts, one 1/2 in. conduit opening, 5.5 in. outlet tube supplied
Choose the inlet tube by duct width: ST-10, ST-25, ST-50 or ST-100. The relay versions are separate numbers, FDBZ492-R, FDBZ492-HR and FDBZ492-PR, and only those take the FDBZ492-RTL test switch.
