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3M™ Macurco™ Carbon Monoxide Detector and Controller
Carbon Monoxide Detector With Fan and Alarm Relays
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What's special about this fixed gas detector?
Carbon monoxide buildup is an unseen hazard often overlooked in enclosed or poorly ventilated structures with gas powered machinery and automobiles. Whether it be an enclosed parking garage, automotive maintenance facility, or warehouse with a forklift, carbon monoxide levels could easily rise undetected and become a serious hazard to your customer's, employee's, or loved one's health, with death being the worst case scenario. 3M™ Macurco™ brand of gas detectors and exhaust fan controllers are a safe, secure, and reliable way to make sure your place of business, work, or home is properly protected and monitored from these unseen dangers. |
- Adjustable fan relay activates your exhaust fans at 35 ppm or 25 ppm averaged over 5 minutes, for removing harmful CO from enclosed or poorly ventilated areas
- Alarm relay activates when CO levels are reaching harmful levels (100 ppm of CO over 30 minutes, or 200 ppm of CO over 10 minutes)
- Quality long-life, solid state sensor provides reliable service for up to 7 years
- Operating light reflects the system status of the controller
- Micro computer controlled to provide reliable operation and internal supervision: any internal problem or detection problem/malfunction will cause exhaust fans to turn on automatically to prevent unnoticed or undetected carbon monoxide gas build up
- Meets UL 2034 standard
This product has starred in our Product Showcase Blog! Click here to check it out.
| PART # | 3M-CM-21A |
| Price | $293.97![]() |
| Power | 3 watts from 12 to 24 VAC or VDC |
| Current | 12 V - 0.25 amps, 24 V - 0.12 amps |
| Weight | 0.55 lbs |
| Size | 4 1/2" x 4" x 2 1/8" |
| Color | Gray |
| Connections | 7 each - #20 Wires x 6" |
| Mounting Box | (not included) 4" x 4" Electric Box |
| Fan Relay | 5 amp, 240 VAC, pilot duty, SPDT |
| Fan Relay Actuation | 35 or 25 ppm CO after 5 minutes |
| Alarm Relay | 0.5 amp 200 V, 10VA |
| Alarm Relay Actuation | 100 ppm CO after 30 minutes or 200 ppm CO after 10 minutes |
| Operating Environment | 0 to 125 F, 10 to 90% RH |
| Repeatability | ± 10% at 50 ppm calibration point |
| Linearity | ± 10% |
Carbon Monoxide Exposure: ppm CO vs. Time: |
||||
| CM-21A Fan Relay | 200 ppm CO | 100 ppm CO | 50 ppm CO | 35 ppm CO |
| 5 minutes | 5 minutes | 5 minutes | 5 minutes | |
| CM-21A Alarm Relay | 10 minutes | 30 minutes | None | None |
| UL 2034 Standard | 35 minutes | 90 minutes | No Standard | No Standard |
| OSHA Standard | No Standard | No Standard | 8 hr TWA | No Standard |
| UBC Standard | 60 minutes | No Standard | 8 hr TWA | No Standard |
| PART # | DESCRIPTION | PRICE Add Quantity at Checkout |
| 3M-CM-21A | 3M Macurco Fixed Carbon Monoxide Gas Detector and Fan Controller | $293.97![]() |
This product has starred in our Product Showcase Blog! Click here to check it out.
MANUALS & USER GUIDES -
- CM-21A User Guide (PDF)

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CATALOG - PDF
For your convenience, we have made our brochure and catalogs available online in PDF format. Downloading the PDF catalog will take you no more than 5 minutes, so you won't have to wait days for the print catalog. PDF catalogs include links to our products: just click on the hyperlinked product headings, and you'll be directed right to our website.
Office
PDF Catalog 2 MB
Automotive
PDF Catalog 2.6 MB
Aerospace/Aircraft
PDF Catalog 2 MB
Utilities & Energy
PDF Catalog 3.7 MB
Datacom/Telecom
PDF Catalog 5.7 MB





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