How Do I Wire and Use a COSMO-2W Combination Smoke/CO Detector?

Wire and use the COSMO-2W by connecting the first COSMO-2W to the COSMOD-2W. Wire each additional COSMO-2W in parallel, connecting to the previous device. Connect the COSMOD-2W to the alarm panel using one zone for smoke, and one zone for carbon monoxide. A maintenance zone can also be used.

The purpose of the System Sensor COSMOD-2W is to cause multiple COSMO-2W devices that are connected to it to all sound in sync with one another if any one of these devices initiates an alarm. For this reason, this configuration is really only worthwhile if multiple smoke/CO devices will be in use, particularly over a relatively large area. Because there are now wireless smoke detectors, or combination smoke/CO detectors that support the "One-Go/All-Go" feature, if only a couple of devices will be used, wireless is the route to take when possible.

Because the COSMO-2W combination Smoke/CO detectors are not being connected directly to the alarm panel, a power reset will not occur automatically after an alarm has been triggered. For this reason, a trigger or relay must be used to perform the reset after an alarm. This is much like the one required when 4-wire smokes are used. This FAQ assumes the COSMO-2W and COSMOD-2W are being used with a Vista P-Series Panel, such as the Vista-20P.

COSMOD-2W Terminal Layout:

The diagram below shows the proper wiring, along with some notes on programming. Each numbered item will be further explained below the diagram:

1. Power Input. One side of the COSMOD-2W power input should be wired through a relay. This relay will provide a power reset after a fire alarm. Either a 4204, 4229, or a low current relay triggered by Output 17 or Output 18 can be used. The trigger can not be used for this by itself, as it does not supply enough current. Regardless of which output is used, the programming will be the same. The relay or trigger will activate on Zone Type. The Zone Type is 54 (Fire Reset) the action will automatically be "Close for 2 seconds" when ZT 54 is selected. The output number will either be the relay which was enabled through Output Device Mapping [*79], or will be either Output 17 (trigger 1) or Output 18 (trigger 2). If a supplementary power supply is used to power any portion of this setup, it must have a common ground with the panel. In this case, DC negative from the power supply should be connected to terminal 4 on the Vista P-Series Panel.
2. Zone Selection. Any zone other than Zone 1 can be used for the smoke input. When Zone 1 is programmed as a fire zone, the Vista P-Series Panels assume 2-wire smokes are being used, and that the zone will reset automatically after a fire alarm. For this reason, smoke reset logic for the relay or trigger will not kick-in after a fire alarm on Zone 1. Use any other hardwired zone for this.
3. Bell Resistor. On Vista-15P/20P rev 9 or higher and newer Vista-21iP panels, an 820 Ohm resistor is included for bell supervision. In addition, there is a programming question that allows bell supervision to be enabled or disabled. Even if bell supervision is disabled via programming, the 820 Ohm resistor must be wired in parallel on the bell terminals. This is because supervision voltage is present on the bell terminals, whether the feature is enabled or not. The 820 Ohm resistor will bring this voltage down so that it doesn't interfere with the COSMOD-2W operation.
4. Dipswitch 1. For the configuration shown, where the bell output is being used to trigger the COSMOD-2W, Dipswitch 1 must be in the ON position. This is the default setting.
5. End-of-Line Resistors. The panel EOLR must be enabled for the Smoke and CO zones, and they must be connected in parallel on the COSMOD-2W. The panel will supervise the wiring between itself and the COSMOD-2W. The COSMOD-2W will supervise the wiring between itself and the COSMO-2W Smoke/CO units. It comes with its own 3.9K resistor. This FAQ shows how to wire multiple 2-wire smokes in parallel.
6. CO Trigger Input. A second relay must be used to trigger the COSMOD-2W CO input. This is what tells the COSMOD-2W to sound all detectors in temporal 4 for a Carbon Monoxide alarm. Again, a 4204, 4229, or low-current relay activated by an on-board trigger can be used. The common terminal for this relay will connect to the COSMOD-2W CO Trigger In terminal. Normally Open will connect to a positive power source, such as terminal 5 on the Vista P-Series Panel. The programming will be activated by Alarm on a Zone Number or Zone List (if more than one CO zone is in use on the panel). The Action will be Close and Stay Closed. The programming to stop the relay will be activated by Zone Type, Zone Type 22, and Action 0 - Off, again making sure to point to the correct Relay or Trigger enabled in [*79].