Macurco CM-12 Carbon Monoxide Gas Detector

The Macurco CM-12 is a 100-240 VAC carbon monoxide detector, ventilation controller, and analog transducer with a 0-200 ppm CO measurement range for commercial parking garages, boiler rooms, and vehicle maintenance facilities. It features a 5A SPDT fan control relay, configurable 0.5A alarm relay, 4-20 mA analog output, and optional digital concentration display and audible buzzer. The CM-12 supports adjustable ventilation thresholds, fan delays, and alarm settings, with manufacturer-stated coverage of up to 7,500 square feet per detector.

Macurco CM-12 100-240VAC Carbon Monoxide Detector and Ventilation Controller

The Macurco CM-12 is a line-voltage carbon monoxide (CO) detector, ventilation controller, and analog gas transducer designed for commercial and industrial air-quality monitoring applications. The device continuously monitors carbon monoxide concentrations within a 0-200 parts per million (ppm) measurement range, providing automatic control of ventilation equipment and external alarm systems when programmed CO thresholds are reached. Designed for parking garages, vehicle maintenance facilities, loading areas, boiler rooms, and other spaces where combustion equipment or vehicle exhaust can produce carbon monoxide, the CM-12 combines gas detection, relay-based ventilation control, and analog concentration reporting within a single wall-mounted unit. The manufacturer identifies a coverage area of up to 7,500 square feet per detector, subject to building layout, airflow patterns, applicable codes, and system design requirements. The CM-12 can operate independently or integrate with compatible Macurco control panels and building automation systems.

The Macurco CM-12 operates on 100-240 VAC, 50/60 Hz primary power using an integrated switching power supply, eliminating the need for a separate low-voltage power converter. The detector incorporates a 5-amp, single-pole double-throw (SPDT) fan control relay rated for 240 VAC pilot duty, allowing it to control appropriately rated ventilation starters and control circuits. Fan activation thresholds can be configured for 15, 25, 35, 50, or 100 ppm CO, with a factory-default activation setting of 35 ppm. Programmable fan activation delays of 0, 1, 3, 5, or 10 minutes and minimum ventilation runtimes of 0, 3, 5, 10, or 15 minutes help reduce unnecessary fan cycling while maintaining automatic exhaust control. The fan relay supports latching or non-latching operation, while a separate 0.5-amp alarm relay, rated at 120 VAC and 60 VA, provides selectable normally open or normally closed operation. Alarm thresholds are configurable at 50, 100, 150, or 200 ppm, with 200 ppm as the factory-default setting.

The CM-12 includes a 4-20 mA analog current-loop output representing carbon monoxide concentrations from 0 to 200 ppm, enabling integration with compatible building automation systems, gas monitoring controllers, and remote monitoring equipment. Its optional three-digit LED display provides direct concentration readings, while the internal audible buzzer produces an 85 dBA warning measured at 10 centimeters when enabled. Both the display and buzzer can be configured independently, with each disabled in the factory-default configuration. The detector also incorporates internal fault supervision that activates the fan and alarm relays when specified detector failures occur, supporting identification of equipment conditions requiring maintenance. Its factory-calibrated sensing system supports field calibration and functional testing using compatible Macurco calibration equipment and certified carbon monoxide test gas. These capabilities allow the CM-12 to provide standalone ventilation control, remote gas concentration monitoring, and configurable high-level CO alarm signaling without requiring separate detection and control devices.

The Macurco CM-12 features a dark gray enclosure measuring approximately 4-1/2 inches high, 4 inches wide, and 2-1/8 inches deep, designed to mount directly over a standard 4-inch square electrical box. The electrical box is sold separately, and the detector housing serves as the installed box cover. Its plug-in and terminal connections accommodate primary AC power, ventilation control, auxiliary alarm signaling, and analog monitoring circuits. The detector is rated for operation from 0 F to 125 F (-18 C to 52 C) at 10-90% relative humidity, noncondensing, supporting use in commercial mechanical spaces and enclosed vehicle facilities. The CM-12 is ETL Listed to applicable UL 61010-1 and CAN/CSA C22.2 No. 61010-1 electrical safety standards and is designed for commercial carbon monoxide exposure monitoring rather than residential household CO alarm applications. Unlike the Macurco CM-6, which operates on low-voltage AC or DC power, the CM-12 accepts 100-240 VAC line voltage directly. Its adjustable CO thresholds, high-capacity ventilation relay, programmable alarm output, analog communication interface, and compact mounting configuration provide a comprehensive solution for commercial carbon monoxide detection and automated ventilation management.