Understand How Your Test Instruments Calibrates

While working around potential CO generation sources it is important to be certain that the work site is safe for the technician.  Manufacturers of CO test instruments typically design the instrument to calibrate either ‘manually’ or ‘automatically’.

Automatic calibration results in the instrument calibrating to 0 regardless of ambient CO levels.  Bacharach’s PCA and Model 300 perform calibration in this manner.  To provide a margin of safety, these instruments will display a CO sensor error should ambient CO levels be in excess of approximately 80 ppm during the 60 second calibration cycle.

These instruments can still be used for CO source investigation and protection of the technician; it simply has to be calibrated outside, before entering a building.

Bacharach’s Monoxor II is specifically designed for CO source investigations.  As such, it performs a ‘manual’ calibration during it’s brief warm up period.  If there are 25 ppm’s (CO) in the ambient air, for example, the instrument immediately displays that reading.

During development of the newest combustion analyzer (the Fyrite Pro), it was decided that the type of calibration should be up to the technician.  This instrument can be easily set up for either ‘manual’ or ‘automatic’ calibration.

Caution:  All manufacturers of CO test instruments recommend the sensor be calibrated every 6 months using a tank of calibration gas.  This can either be done at an authorized service center or by the user with a calibration kit supplied by the manufacturer.