A list of possible causes

Harvey Ramer

of unstable or slowly creeping CO readings while O2 and CO2 are stable and correct. Oil boiler. Correct nozzle and tried a couple. EK1. No flue blockage. No flame flutter.

STEVEusaPA

Are you running out of combustion air, either by not having enough, or someone is using a dryer, range hood, etc?
Does your analyzer have a nox filter?
Did you check with another analyzer?
It's a tricky diagnosis because you would expect to see changes in the other readings, like excess air with a change in CO

Bob Bona_4

I'm thinking instrument problem, the CO2 has to change with the O2.

ChrisJ

Bob Bona said:

I'm thinking instrument problem, the CO2 has to change with the O2.

I thought the same thing, but couldn't remember what most analyzers calculate vs measure.

Harvey Ramer

Source of combustion air is not a problem. Or shouldn't be given its a wide open basement in an old house. I have seen this before on a Burnham LE series and that turned out to be the nozzle. This one has me slightly puzzled. I played with the air adjustments and changed the CO2 all the way from 12.5 to 10.4. The O2 moved accordingly but it didn't seem to make much difference in the CO. It just slowly but surely kept climbing. One number increase every couple seconds. It never reached 300 because the system wouldn't allow long enough run times.

Maybe I need to take a closer look at my analyzer. It's a Bacharach in-Tech.

ChrisJ

What do you do when something like this happens?
Customer needs heat, it's cold out, the boiler appears to be running clean, your personal CO monitor isn't making a sound but your analyzer says the CO in the flue keeps creeping, but you start questioning the analyzer?

Do you disable the equipment? Do you assume the analyzer is faulty and leave the boiler on until you confirm your analyzer is good or bad?


My guess is you leave the boiler running as long as it appears safe to the best of your knowledge and go and get the analyzer looked at and come back afterwards.

But I'm curious how most guys behave in this situation.

Harvey Ramer

I don't think there is a rule for that Chris. In some cases I will shut down the system and in some cases I won't. It's a judgement call that you have to make in the field. If I feel confident that no one will be in harms way and the system isn't running dangerously I will normally leave it on until I get everything resolved to my satisfaction. If I feel like I maybe won't be allowed back, I'll shut it down.