On November 15, 2011, 3M discontinued model CM-21A. The direct replacement is model CM-6. Click here to view the CM-6 product page
- CM-21A provides CO detection and automatic exhaust fan control for automotive maintenance facilities, enclosed parking garages, warehouses with forklifts, etc.
- Selectable fan and alarm relay activation
- 5 amp SPDT fan relay controls starters of exhaust fans
- 1/2 amp N.O. or N.C. alarm relay connects to warning devices or control panels
- CM-21A mounts on a standard 4x4 electrical box and becomes cover for the box
- Supervised system: any internal detector problem will cause the fan relay to activate
- CMS-FCK calibration kit is available. One screw allows access for calibration.
The CM-21A is a low voltage, dual relay Carbon Monoxide (CO) detector and Automatic ventilation controller. The CM-21A uses a microcomputer controlled, electronic system to measure the concentration of CO and calculates when the relays should be actuated. The CM-21A is low maintenance with no periodic calibration needed and a long life (7 to 10 years) solid-state sensor.
|Power ||3W from 12-24 VAC or VDC |
|Current ||12V - 0.25 A, 24 V - 0.12 A |
|Size ||4 1/2" x 4" x 2 18" |
|Connections ||7 each #20 wires, 6 inches long |
|Mounting Box (not included) ||4 x 4 electric |
|Fan Relay ||5A, 240 VAC, pilot duty, SPDT |
|Fan relay actuation ||Selectable at 25ppm, 35ppm (default), 50ppm or 100ppm CO within 5 minutes |
|Alarm Relay ||0.5A 200 V, 10 VA |
|Alarm relay actuation ||Selectable at 100ppm CO within 3 hours or 200ppm CO within 10 minutes |
|Operating Environment ||0-125°F, 10 to 90% RH |