System Sensor COSMO-2W — i4 series 12/24 V system-connected combination carbon monoxide and photoelectric smoke detector, 2-wire, with an 85 dBA sounder, a field-replaceable CO cell and RealTest functional gas testing. Plug-in head with base.
The COSMO-2W puts photoelectric smoke sensing and an electrochemical CO cell in one device, so a dwelling unit needs one back box and one wire run instead of two. It sends distinct smoke and CO signals to the panel and sounds Temporal 3 for smoke and Temporal 4 for CO, so occupants and the monitoring station can tell the two events apart. The COSMO-2W cannot be wired directly to a control panel — the COSMOD2W 2-wire interface module is required. That module connects up to 12 detectors to a panel using only two or three zones, interconnects all detector sounders so one alarm sounds them all, and drives the EZ Walk loop test and the maintenance signal. Drift compensation and smoothing algorithms hold smoke sensitivity steady, sensitivity is read with the SENS-RDR, and the CO cell is replaced tool-free in the field with a CO-REPL at end of life instead of scrapping the detector. Base included.
Specifications
| Model |
COSMO-2W (i4 series) |
| Detection |
Photoelectric smoke and electrochemical CO |
| Wiring |
2-wire, system connected; requires COSMOD2W interface module |
| Operating voltage |
12/24 VDC nominal; minimum 8.5 VDC, maximum 35 VDC |
| Maximum standby current |
50 µA |
| Maximum alarm current |
50 mA (2-wire) |
| Maximum reverse polarity current |
20 mA |
| Maximum start-up current |
200 µA |
| Maximum start-up capacitance |
0.10 µF |
| Audible signal |
85 dBA — Temporal 3 for smoke, Temporal 4 for CO |
| Smoke sensitivity |
2.5%/ft nominal |
| CO cell |
Field-replaceable, 10-year end-of-life timer that signals the panel and chirps |
| Operating temperature |
32°F to 122°F (0°C to 50°C) |
| Storage temperature |
14°F to 158°F (−10°C to 70°C) |
| Operating humidity |
20 to 95% RH |
| Dimensions (including base) |
5.5″ diameter × 2.5″ depth |
| Weight |
9.2 oz (261 g) |
| Input terminals |
14 to 22 AWG, SEMS screws |
| Mounting |
3.5″ and 4″ octagonal, single-gang, 4″ square, 2 × 4″, 3.5″ and 4″ round ceiling back boxes; or direct to wall or ceiling |
| Listings |
UL 268 (Fire Protection Signaling Systems) and UL 2075 (Carbon Monoxide Gas Detection) |
| LED — standby |
Green blinks every 5 seconds |
| LED — power up |
Green, red and blue all blink every 5 seconds |
| LED — smoke alarm |
Red on, sounder Temporal 3 |
| LED — CO alarm |
Blue on, sounder Temporal 4 |
| LED — smoke and CO alarm |
Red and blue on, sounder Temporal 3 |
| LED — smoke maintenance |
Red blinks every 5 seconds |
| LED — CO trouble |
Blue blinks every 5 seconds |
| LED — end of life |
Blue blinks every 5 seconds with intermittent sounder |
Installation notes
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The COSMOD2W module is not optional: the ordering information lists the 2-wire interface module as required to use COSMO-2W models. Budget one module per group of up to 12 detectors and two to three panel zones (smoke, CO, and an optional trouble zone). A COSMO-2W bought without a module cannot be commissioned.
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Match the module to the wiring type: COSMOD2W works with COSMO-2W combination detectors and i3 2WTA-B smoke detectors. COSMOD4W works with COSMO-4W and 4WTA-B. The two are not interchangeable.
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No RRS-MOD needed: the i4 module interconnects the sounders of all devices connected to it, so a separate reversing relay/synchronization module is not required for sounder interconnection. Optional trigger inputs let multiple modules sound together.
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Two tones mean two events: Temporal 3 is smoke and Temporal 4 is CO. Occupant instructions differ for the two — evacuate for smoke, move to fresh air and ventilate for CO — so do not describe the sounder as a single alarm tone.
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Replace the cell, not the detector: at the ten-year end of life the detector signals the panel and chirps. Fit a CO-REPL replacement cell, which changes in the field without a tool.
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Retrofits into i3 loops: the i4 series is compatible with existing i3 2WTA-B installations, so CO monitoring can be added to an i3 system with the appropriate module rather than rewiring.
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Loop resistance limit: the 2-wire module allows a maximum loop wiring resistance of 50 ohms. That is a much tighter limit than the 300 ohms permitted on the 4-wire module — check conductor length and gauge before pulling wire.
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EZ Walk timing: the EZ Walk loop test is available for six minutes after power up or a panel reset. If the window closes, reset the panel again rather than assuming a fault.
Related models and accessories
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COSMO-4W — 4-wire version of the same combination detector; 40 mA maximum alarm current, uses the COSMOD4W module and requires an EOLR-1 end-of-line relay
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COSMOD2W — required 2-wire interface module; supports Style D / Class A IDC wiring and EZ Walk
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CO-REPL — replacement CO cell for COSMO-2W and COSMO-4W
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SENS-RDR — wireless smoke sensitivity reader
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2WTA-B — i3 smoke-only detector with sounder, compatible with the same COSMOD2W module
Specifications taken from the System Sensor data sheet “i4 Series Combination CO/Photoelectric Smoke Detector,” document CODS303-03 (11/07/2017). Manufacturer specifications are subject to change without notice.
