Low Co ppm after Kane 455 service

[RayPlumb]

Hi . Just had my Kane 455 back after 5th year service. Friday used it to check a repaired old oil heatslave combi. Repair did not alter combustion settings. I had serviced the boiler in April and expected similar combustion results. Although the Co was 6ppm in April it was about 41ppm. All other setting unchanged. I then yesterday checked with my own Grant combi 21e and usually get a co of about 34ppm. This time co of 4ppm. Now Im thinking either my AGA is faulty after service or was faulty all last year? I looked on Kane web site and found this under FAQ 's -
KANE analysers are equipped with improved CO sensor technology which is less cross sensitive to NOx emissions . This may result in lower than anticipated CO readings when used on light oil fired and other high temperature appliances.
Any one know how this improved CO sensor works ? surely the number of Co ppm in the flue is just that. Do you think my analyser is faulty ?
Thanks
Ray

 

[ShaunCorbs]

I would say fga is faulty as it’s unlikely it’s that low

 

[SJB060685]

CO ppm can change at anytime. You may not have changed any settings but whats to say the nozzle is not functioning different now from April.?
I'd expect a FGA sent away from calibration and replacement of sensors will be tested properly.
Have you got a spare FGA you can cross check with?

 

[RayPlumb]

CO ppm can change at anytime. You may not have changed any settings but whats to say the nozzle is not functioning different now from April.?
I'd expect a FGA sent away from calibration and replacement of sensors will be tested properly.
Have you got a spare FGA you can cross check with?

No , nothing to compare with other than previously checked boilers. I have the certificate, Ill phone Kane tomorrow see what they say.
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Spoke to Kane today. Apparently the new CO sensors now only measures the CO and not a combination of CO and NOx as previous sensors with light oil. He asked me to check with a Nat Gas boiler and should expect between 30-70ppm
Which I did and got 36ppm thus proving it is reading the CO.