When turned on does the PCA read the actual ambient carbon monoxide levels?
The PCA is designed to do an ‘automatic’ CO calibration during it’s 60 second warm up period. This means that it will attempt to calibrate to zero (0) irregardless of existing ambient CO levels. As a safety feature, the instrument will go into a ‘CO sensor error’ mode should ambient levels of CO be in excess of approximately 75 ppm’s. Should that occur, immediately vacate the area, go outside (or other area with ‘clean’ air) and turn the instrument on again. If it successfully calibrates this time, there was, in all likelihood, potentially dangerous levels of CO in the original location.