D4120A 4-Wire Photoelectric Duct Smoke Detector with Sampling Tube
The D4120A Duct Smoke Detector is a 4-wire photoelectric detector designed to monitor airflow within compatible HVAC duct systems for the presence of smoke.
Its integrated low-flow detection technology samples air moving through the duct. When sufficient smoke is detected, the unit can initiate an alarm signal and support compatible HVAC control functions, such as fan shutdown, to help limit the movement of smoke through the ventilation system.
The multi-voltage design supports 24V AC/DC or 120V AC operation and provides alarm, supervisory and auxiliary relay contacts for compatible control-panel and HVAC interfaces. This is a 4-wire device and is not intended for 2-wire applications.
A pivoting housing allows the detector to be arranged in square or rectangular configurations and mounted on compatible round or rectangular ductwork. The plug-in photoelectric sensor head supports easier testing, servicing and replacement.
This listing includes a compatible sampling tube, commonly described as the rod. The sampling tube must be correctly sized for the width of the HVAC duct to ensure proper air sampling. Confirm the included tube length and duct dimensions before ordering.
Key Features
- Four-wire photoelectric duct smoke detector
- Integrated low-flow detection technology
- Designed to sample air within HVAC ductwork
- Includes compatible sampling tube or rod
- Operates on 24V AC, 24V DC or 120V AC
- Alarm and supervisory relay contacts
- Auxiliary relays for compatible fan-shutdown applications
- Air-velocity operating range of 100 to 4,000 feet per minute
- Pivoting housing for square or rectangular configurations
- Mounts to compatible round or rectangular ductwork
- Replaceable plug-in sensor head
- Accessible Test/Reset button
- LED status indication
- Cover-tamper monitoring
The detector is designed for airflow speeds from 100 to 4,000 feet per minute, operating temperatures from approximately -20°C to 70°C, and relative humidity from 0% to 95% non-condensing.
Best Used For
- Commercial HVAC systems
- Supply-air duct monitoring
- Return-air duct monitoring
- Office buildings
- Retail facilities
- Schools and institutional buildings
- Warehouses
- Industrial facilities
- Compatible rooftop HVAC equipment
- Fire-alarm and mechanical-control projects
Important Installation Information
A duct smoke detector is intended to monitor smoke within an operating air-handling system. It is not a replacement for required open-area smoke detectors or a complete building fire-detection system. The detector requires electrical power, airflow and a properly installed cover to operate as designed.
Installation, wiring, sampling-tube selection, testing and maintenance must follow the manufacturer’s instructions, the applicable fire and building codes, and the requirements of the local authority having jurisdiction. Installation should be completed by qualified fire-alarm or HVAC personnel.
