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.

Product Highlights

  • 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


Unit of Measure

Range (CO)

N/A 0 - 50 ppm


N/A +/- 10 of reading %.

Alarm Level Setting

N/A Alarm 1: 5 ppm CO, user adjustable Alarm 2: 10 ppm CO, user adjustable Alarm 3: 20 ppm CO, user adjustable, All adjustable between 1 to 50 ppm

Audible Alarm

N/A 105 dB at 12 in

Inlet Size

N/A 1/4" NPT Female

Operating Temperature Range

N/A 32° to 104°F ºF

Power Requirements

N/A 100 to 240 VAC and/or 12 VDC, 15W


N/A 2 lbs

General Description


Display: High-contrast, backlit


Resolution: 1 ppm


Alarms:   Visual Gas Alarm: 3 red LEDs, Visual Power Fault: Green/Red LEDs, Audible Alarm: 105 dB at 30 cm (12 inches)


Operating Power: 110 VAC, 220 VAC and/or 24 VDC, 15W


Power Connection: Supplied with strain relief for 0.20 to 0.35 inch diameter cable


Outputs: Relays: 4 Form C, 10A SPDT contacts, 3 gas alarms and 1 fault, Analog: 4-20mA, Digital: RS-485 COM port interface using Modbus RTU


Sensor: Electrochemical


Response Time: t90 = 30 sec


Accuracy: +/- 10% of reading


Temperature Range: 32° to 104° F (0° to +40° C)


Inlet Air Line Connection: 1/4 inch NPT female


Air Line Sample Hose to Monitor: 5 foot length


Inlet Pressure: 60 to 150 psi, air supply lines, 55 psi regulated to monitor


Enclosure: Polycarbonate


Dimensions: 7.1 W x 6.1 H x 3.5 D inches (18.2 W x 15.5 H x 8.9 D cm)


Weight: 2 lbs (0.9 kg)






Range: 0-50 ppm CO


Alarm Levels: Alarm 1: 5 ppm CO, user adjustable, Alarm 2: 10 ppm CO, user adjustable, Alarm 3: 20 ppm CO, user adjustable


Alarm Adjustment: All three alarms are user adjustable between 1 to 50 ppm