Fieldpiece Combustion Analyzers (CAT45, CAT85) that have firmware version v1.1 and earlier do not default the CO AIR FREE value to the highest reading, which is also known as [COAF], [CO Undiluted], or [CO at 0% O2 Reference].
To ensure the CO AIR FREE reading is correct, the user should go to Settings and change the O2 Reference from the default number of 6% to 0% [zero oxygen]. This change accurately displays the CO AIR FREE value to comply with BPI-1200 and AHRI 1260 Standards.