CO2/O2

mikeGlosta

My technician's tag reading. after tune-up, reads CO2/O2 5.5%
Can you explain what this number means, is it where it should be, or needs improvement?
Thanks

DJD775

First off I'm not a pro. The 5.5% is the percent oxygen in the flue gas. Take a look at this link for a quick explanation: https://www.beckettcorp.com/bulletins/burners/general/combustion-testing-oxygen-or-carbon-dioxide/

EBEBRATT-Ed

Can't say for sure but that looks (the 5.5%) like an 02#. Perfect co2 on oil is about 15%. But you can't achieve that. You usually adjust for 11-12% with a modern burner. You total of Co2 and O2 add up to the perfect # so in you case 15-5.5o2= 9.5 Co2.

Numbers for gas or other fuels are a little different