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Carbon Monoxide (CO) Monitor
Methane monitor Features of the Guardian plus CO Monitor
  • Continuous monitoring of carbon monoxide concentrations
  • Long term stability - infrequent calibration
  • Low maintenance
  • Audible and visual alarms and relays signals
  • Easy to read 4 digit LCD display
  • ISO9002
  • RS232 option
  • For CO air quality monitors follow these links
    1) Hand held portable CO monitor
    2) Air quality wall mount  CO monitor


The Guardian gas monitor uses a special non dispersive dual wavelength infra red sensor unit which has no moving parts. This ensures the long term stability of the instrument without the need for frequent recalibration. The gas is metered into the measuring system with a built in sample pump. Remote sampling can be performed by connecting a 5 mm diam sample tube to the gas inlet. This tube can be up to 90 feet long. The instrument is enclosed inside a tough plastic enclosure rated IP54 against the ingress of water and dust further increasing its long term reliability. The two independent alarm levels are set on the front panel and other options for analog output, alarm designation, buzzer and flow indication are set on on a dipswitch. The Guardian is designed to monitor the high levels of CO typical of combustions and industrial processes. For low level CO safety monitors click here

Air Quality Monitor, CO, here 

Applications of
CO monitoring

Combustion processes
Health and safety
Related products
Air Quality Monitor, CO, CO2
This instrument also available as a methane or carbon dioxide monitor.

See also
Flue gas and emissions analyzer 

Measuring range CO carbon monoxide 0 - 10 % 
Accuracy +/- 2% of the range
Stability +/- 2% of the range over 12 months
at zero +/- 0.3%
at span +/- 1.5 %
Response time T90 = 30 secs from sample inlet
Operating temperature 0 - 40 degs C
Warm up time operational 3 mins
Humidity unaffected 0 - 100% RH non condensing
Alarms - modes set up with a dipswitch inside the unit 2 alarms setting each with high/low
relay contacts for each alarm norm/latch
Buzzer for one or both alarms
Low flow alarm/warning
Display 4 digit LCD and 4 LEDs for alarms and flow
Relay contacts 8 A 24 DC
Pump 1 L/min
Power 110/220 VAC
Weight 2.5 kg
Dimensions 267 x 258 x 148
Enclosure IP54
Ordering Information
Model Description Part No Price view shopping cart
GuardCO Carbon Monoxide monitor GUARDCO  $2350.00 Add item to shopping cart
RS232 RS232 interface card RS232 $325.00

Topac Inc 231 CJC Highway, Cohasset MA 02025 USA
Tel: 781 740 8778 Fax: 781 740 8779 e-mail:

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