CO-GUARD is a compact, easy to install and operate compressed airline carbon monoxide monitor that meets OSHA monitoring requirements for Grade D breathing air. The instrument is specifically designed for trouble-free operation, utilizing an electrochemical carbon monoxide (CO) sensor with a life expectancy of up to three years. The CO-GUARD is supplied with a regulator assembly and five foot sample hose, and is factory pre-calibrated.

CO-GUARD incorporates a rotameter for confirmation of proper airflow and has an easy to use software interface that allows users to change alarm points, program relays and perform calibrations in the field. CO-GUARD includes a backlit digital display, audible and visual alarms with three alarm levels. The power LED doubles as a fault indicator should a fault occur. The audible alarm features a four minute audio defeat option for alerts below alarm level three. The standard regulator for COGUARD is designed to accept an input pressure between 60 to 150 psi (pounds per square inch). The output pressure of the regulator is set to 55 psi to provide a flow rating around ½ liter per minute or 1 scfh (standard cubic feet per hour) as viewed on the rotameter. It is simple to replace the sensor and recalibrate the instrument in the field.


• Meets OSHA 1910.134 compressed breathing air monitoring requirements
• Continuous carbon monoxide monitor for compressed breathing air
• Proven electrochemical sensor technology
• Simple push button operation
• Easy to install compact design
• User programmable alarms and high capacity relays
• Low maintenance field replaceable sensor



General Specifications

DisplayHigh-contrast, backlit
Resolution1 ppm
AlarmsVisual Gas Alarm: 3 red LEDs Visual Power Fault: Green/Red LEDs Audible Alarm: 105 dB at 30 cm (12 inches)
Operating Power110 VAC, 220 VAC and/or 24 VDC, 15W
Power ConnectionSupplied with strain relief for 0.20 to 0.35 inch diameter cable
Relays4 Form C, 10A SPDT contacts, 3 gas alarms and 1 fault
DigitalRS-485 COM port interface using Modbus RTU
Response Timet90 = 30 sec
Accuracy+/- 10% of reading
Temperature Range32° to 104° F (0° to +40° C)
Inlet Air Line Connection1/4 inch NPT female
Air Line Sample Hose to Monitor5 foot length
Inlet Pressure60 to 150 psi, air supply lines, 55 psi regulated to monitor
Dimensions7.1 W x 6.1 H x 3.5 D inches (18.2 W x 15.5 H x 8.9 D cm)
Weight2 lbs (0.9 kg)
Range0-50 ppm CO
Alarm LevelsAlarm 15 ppm CO, user adjustable
Alarm 210 ppm CO, user adjustable
Alarm 320 ppm CO, user adjustable
Alarm AdjustmentAll three alarms are user adjustable between 1 to 50 ppm

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