D4120W — System Sensor InnovairFlex watertight 4-wire photoelectric low-flow duct smoke detector, UL listed as a NEMA Type 4 watertight enclosure for non-hazardous indoor and outdoor applications.
The D4120W is the watertight member of the InnovairFlex family: the enclosure protects against falling dirt, rain, windblown dust, splashing and hose-directed water, and the housing and cover material are UV resistant and UL listed. A pivoting housing fits both square and rectangular footprints and mounts to round or rectangular ductwork. The unit senses smoke in demanding conditions — airflow from 100 to 4,000 feet per minute, −4°F to 158°F, and 0 to 95% relative humidity non-condensing — so it can be mounted on rooftop HVAC equipment and in other harsh environments. A plug-in sensor head gives superior false alarm immunity. The design keeps the same form, fit and wiring terminations as the standard InnovairFlex unit, adds a ¾-inch conduit knockout for extra wiring space, high contrast terminal designations and built-in short circuit protection against wiring errors, and provides one easy-access Test/Reset button with improved LED status. The patented sampling tube installs from the front or back with no tools, and a patented interconnect feature supports multi-fan shutdown.
Specifications
| Type |
Watertight 4-wire photoelectric low-flow duct smoke detector |
| Enclosure rating |
NEMA Type 4 — watertight, indoor/outdoor |
| Power supply voltage |
20–29 VDC; 24 VAC 50–60 Hz; or 120 VAC 50–60 Hz |
| Max standby current |
21 mA @ 24 VDC; 65 mA RMS @ 24 VAC 60 Hz; 20 mA RMS @ 120 VAC 60 Hz |
| Max alarm current |
65 mA @ 24 VDC; 135 mA RMS @ 24 VAC 60 Hz; 35 mA RMS @ 120 VAC 60 Hz |
| Alarm initiation contacts (SPST) |
2.0 A @ 30 VDC (resistive) |
| Alarm auxiliary contacts (DPDT) |
10 A @ 30 VDC; 10 A @ 250 VAC; ½ HP @ 240 VAC; ¼ HP @ 120 VAC |
| Supervisory contacts (SPDT) |
2.0 A @ 30 VDC (resistive); 2.0 A @ 125 VAC (resistive) |
| Relay contacts provided |
Two DPDT Form-C contacts |
| Alarm response time |
15 seconds |
| Power up time |
35 seconds max |
| Reset time |
0.03 to 0.3 sec with RTS151; 0.6 sec max by power down |
| Reset voltage |
3.0 VDC min; 2.0 VAC min (24 VAC); 10 VAC min (120 VAC) |
| Input capacitance |
270 µF max (24 VDC and 24 VAC); not applicable on 120 VAC |
| Air duct velocity |
100 to 4,000 ft/min (0.5 to 20.32 m/sec) |
| Operating temperature |
−4°F to 158°F (−20°C to 70°C) |
| Storage temperature |
−22°F to 158°F (−30°C to 70°C) |
| Operating humidity |
0% to 95% relative humidity, non-condensing |
| Size, rectangular configuration |
14.38 in (37 cm) length × 5 in (12.7 cm) width × 2.5 in (6.36 cm) depth |
| Size, square configuration |
7.75 in (19.7 cm) length × 9 in (22.9 cm) width × 2.5 in (6.35 cm) depth |
| Weight |
2.5 lbs (1.14 kg) |
| Terminal connections |
Strip and clamp method, suitable for 12–18 AWG wiring |
| Listing |
Housing UL listed per UL 268A specifically for use in air handling systems |
Installation notes
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Watertight only if installed watertight: the data sheet states that watertight conduit and fittings must be used to maintain the watertight properties of this detector, and that the product should be mounted with the conduit holes facing downwards if possible. Standard fittings void the NEMA 4 protection.
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Never wire the auxiliary contacts to a panel initiating circuit. The DPDT alarm auxiliary contacts are for fan shutdown and similar duties. Use the SPST alarm initiation contact for the control panel — the data sheet states this explicitly, and it is a common and serious wiring error.
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Interconnect for multi-fan shutdown: up to 50 D4120W units may be interconnected, and the detector is capable of controlling up to 50 air handling systems when interconnected with other detectors.
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Interconnect rules: all interconnected units must be powered from the same independent supply, and polarity must be maintained throughout — INT+ to INT+, INT/AUX− to INT/AUX−. An alarm can be reset only at the initiating device, not at the interconnected devices.
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Mixing with legacy Innovair: up to 10 DH100ACDC units may be interconnected, and each of the 9 interconnected DH100ACDC units may be replaced by three D4120W units, so a single DH100ACDC can drive either 9 DH100ACDCs or 27 D4120W units.
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Accessory load limits: any combination of accessories may be used provided the loads total 110 mA or less at the Aux output and 50 mA or less at the Alarm output.
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Testing: locally by magnetic switch or the test button on the cover, or remotely with the RTS2-AOS multi-signaling accessory or the RTS151KEY remote test station. The detector also provides a trouble signal if the front cover is removed.
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Sampling tube must match duct width: DST1 up to 1 ft, DST1.5 for 1–2 ft, DST3 for 2–4 ft, DST5 for 4–8 ft, DST10 for 8–12 ft.
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Not a substitute for open area detection: duct smoke detectors are not a substitute for open area smoke detectors, not a substitute for early warning detection, and not a replacement for a building’s regular fire detection system. Refer to NFPA 72 and NFPA 90A.
Related models and accessories
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D4120 — the standard, non-watertight InnovairFlex 4-wire duct smoke detector for protected indoor locations
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2D51 — listed in this data sheet as the 4-wire conventional photoelectric sensor head
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RTS151 remote test station; RTS151KEY keyed remote test station; RTS2-AOS multi-signaling accessory with add-on strobe
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RA100Z remote annunciator alarm LED; APA151 remote annunciator with piezo alarm
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MHR / MHW — mini horn, red or white, for local audible annunciation
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M02-04-00 test magnet; ETX metal exhaust tube; P48-21-00 end cap for metal sampling tubes; DH400OE-1 weatherproof enclosure
Specifications taken from the System Sensor data sheet "D4120W Watertight Duct Smoke Detector," document HVDS006-00 (1/12). Manufacturer specifications are subject to change without notice.
