Eagle/Comb Meter CO Questions

Why won't my analyzer turn off?
UEi analyzers will not power down unless CO is less than 20 ppm, and O2 is above 18% to protect the sensors. Contiue to purge the instrument in fresh air until readings return to near normal zero state (0 ppm for CO, 20.9 for O2). If you have a failed sensor it may prevent the analyzer from shutting down. Please contact UEi to arrange for service.
What is the upper limit for CO on my analyzer?
These models have an upper limit of 2000 ppm. It is not recommended to exceed this level, or operate at an extended time at this level. If the measured values are increasing quickly toward this limit, remove the probe from the flue and make appropriate repairs to the system before testing again. CO levels above 1000 ppm typically indicate that something is out of adjustment.