The analyzer is actually called a flue gas analyzer not and oxygen analyzer. A half decent one costs about $4500 CAD.
Second of all there is no guarantee that the ?speeder jets? are blocked because there is a hundred different styles of burners. They all don?t have spreader jets.
As a 20 industrial boiler technician I?ll say soot usually comes from
- poor combustion air/ or a negative pressure in the room that the boiler sits in
- a dirty of damaged burner. (Most new residential high efficiency boilers use a mesh grill, so it?s probably not damaged.
- newer high efficiency boiler use zero governing gas valves. These valves mix the air and gas. So a faulty one of these would cause your boiler to soot up for sure(I think your engineer fixed the problem)
Last but not least, if the flame is blue, I doubt you?re still sooting. However the boiler more than likely modulates and the flame could be blue at %75 but yellow at %10 so you really need to check the flame in %10 increments