Originally Posted by
Bob Harper
Another indirect CO2 reading using a combustion analyzer is to hold it near the floor and read the O2. If it drops much below the 20.9% norm, you have to ask yourself is this CO2 displacing O2 as it settles near the floor. Now, if you ambient O2 is dropping, you will start getting incomplete combustion and making Bad Stuff, which the analyzer will pick up. Just goes to part of the whole picture.
Great advice Bob!
This is also a great trick to use in the burner compartments of appliances, there should be nothing but close to 20.9% O2 being fed to the burners.
If the burner compartment reads less than that you need to start looking at possible CO2 displacement issues in the burner compartment.
Temperature measurements work well for this also.