Yes, it could be.

 

is this an Ultra299 or Ultra399? if so these are modulating boilers..and are my hands down favorite boiler...How bout a model#

 

It is a series Q90-200, model UB90-200, serial 350500221. A little history on the system: When my boss took over this system it was installed in an apartment complex controlling 15 zones. It was determined (by an engineer) that the system was incorrectly piped (did not have a bypass loop). The engineer told the property owner that the incorrect pipping may have damaged the system. The system has "fluttered" ever since my boss took it over but seemed to get worse after cleaning the burn chamber this fall. Per the recommendation of the Utica Tech Support person, I re-cleaned the burn chamber and that improved the fluttering slightly but not completely. When the combustion intake is removed the fluttering stops. There seems to be a back pressure created at the moment of combustion that causes the pressure switch to flutter which in turn causes the gas valve to flutter. Also, the carbon monoxide reading at the outside exhaust is 4000ppm. That is as high as my reader goes so it may be higher.

Any recommendations or assistance would be greatly appreciated.

 

Did it have the 4000ppm CO with the intake pipe removed?


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Yes

 

hook up a combustion analyzer to the boiler. 4000ppm is way to high and should be corrected to fire under 400ppm. if over 400ppm ANSI standards is to red tag and disable boiler.

could be your venting length, venting size, incorrect venting, etc.....

combustion analyzer should tell you your problems.

 

I have worked on many q90-100 and they had a burner change that resolved ignition rumbling noise.. I will see if I can find the bulletin. I had one last year that I got involved in,,, replace the burner and it was like night and day.. Check your inlet screen (sandwiched in the Fernco)

 

http://www.heatinghelp.com/files/posts/5276/Dunkirk Q90 -200 burner upgrade.pdf

 

Ive found any little cracks in them burner tubes will make them act up.

 

This system already has the new burner tube.

 

Does anyone have a PDF of the manual for this boiler so I can verify correct vent length?

 

http://www.dunkirk.com/uploads/product/literature/2eda10cf8c2d0d1909be7e94ee9628ff.pdf

 

Moved to AOP.

 

Its about time

'The more you know, the more you realize you don't know'

 

Do the pressure switch hoses have an orifice in them close to the barbed fittings? I had one doing what you described and the orifices fixed it.


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