
To successfully install and program your Siemens OH921 Multi Criteria Smoke Detector, follow these guidelines:
Detector Placement: Adhere to NFPA Standard 72 and CAN/ULC-S524 for detector spacing. Install the detector on the ceiling, maintaining a minimum distance of 6 inches from side walls, or on a wall, at least 12 inches from the ceiling. Consider air currents, temperature, humidity, and ceiling when selecting the optimal location.
Avoiding False Alarms: Prevent nuisance alarms by avoiding areas with excessive smoke, high humidity, exhaust fumes, dust accumulation, steam, smoke, or aerosol sprays.
Air Current Considerations: Factor in air movement, as it influences the movement of combustion products toward the detector. Position detectors away from air supply diffusers and closer to air returns.
Programming the Detector: Use the Model DPU Device Programming Unit to program each detector with an address between 001 and 252. Keep a record of the loop and device numbers on the detector label and base to prevent incorrect installation.
Wiring Instructions: The OH921 supports both polarity-insensitive and isolator mode wiring. Refer to the wiring diagrams provided in the manual, ensuring correct wiring based on the mode you have selected.
Detector Mounting: When mounting the detector, make sure wires are dressed flat against the base and routed away from the connector terminals. Securely lock the detector into place in the base by rotating it clockwise.
Testing and Verification: Conduct sensitivity and functional tests using approved test gases, as per NFPA 72 guidelines. Use the DPU for sensitivity measurements and follow the control panel's instructions for functional tests.
Maintenance: All testing and maintenance should be performed by qualified service personnel. Replace any detectors that fail to maintain their programmed sensitivity levels.
By following these procedures, you ensure the Siemens OH921 Multi Criteria Smoke Detector functions correctly, providing reliable fire detection.


