Excessive Chimney Draft on Steam Boiler

ChrisL

I have a 13 unit apartment building 1920's era, with an approx 55' chimney. Worked fine for many years with a WM LGB atmospheric. Last year, had a new boiler installed, which is a 3 pass steel firetube boiler with a Beckett cg10 gas burner. I am a bit concerned that the chimney has such a strong draft at all times, regardless of unit operation. Seems to throw the delicate balance of the burner off, and am wondering if the flow is so strong through the boiler that it is reducing the output of the boiler. Is it possible for the flow through the boiler to be so fast that it prevents the proper heat transfer to the boiler?

Back when it was installed last year, the power burner would lockout frequently, as the draft would throw off the proper mixture. The burner would go into a bad reverberation as well. The beckett rep came out, but was unable to tune it to satisfaction, and recommended a draft damper, which was installed, with little change. The burner tube was swapped out, which resulted in much better reliable operation, but I think the chimney makes it very temperamental. I can feel air going through the burner when idle, and checking the draft damper at idle also shows a strong constant flow through the boiler.

Anyone have any solutions or advice?

Thanks,
ChrisL

EBEBRATT-Ed

Add a barometric damper, maybe 2 of them with a 55' stack. The installer should have done this.

Get someone to set this up properly with a combustion analyzer.

You old boiler had a draft hood so it wasn't a problem (other than heated building air going for a ride up the stack)