First post here, please be patient.
I'm at a pharmaceutical facility that's been facing some issues for a couple of years with its boilers. Many contractors have had opinions and none of them have turned in to real solutions, so I'd like a consensus on the problem.
We have 2 low-pressure Burnham firetube boilers, I'm currently at home and don't have any specs with me, and they've been going off on low water in the early morning a couple of times a week(or more) for as long as I've been at this facility. From what I've seen, we've had some carryover issues, even in the summer, and this has lead to a feed water tank that has overflowed more times than I would care to count.
My boss dug up a steam survey today from 7 years ago that's mostly relevant, but after adding in the new loads, it looks peak load is at 95-110% of boiler capacity. This is one major issue that will be addressed(hopefully before winter); it's in management's hands. So this overcapacity could really explain the problems we've been having in the winter, but I'm not sure why it's persisting(thought not to such a great degree or as frequently) in the summer. We have a boiler chem contractor that says the chemistry is fine, so I'm not too sure that that's the problem. However, after reading some stuff on this site and from various other sites, I noticed what could be a problem in the near boiler piping.
If I can, I'll provide a drawing tomorrow. But, for now, let me attempt to explain.
The larger boiler's riser(Boiler 1) goes up maybe 24" from the top of the boiler before turning at a 90, continues straight from there for about 30" before turning at another 90 and then about 5' before turning down into the common header. In that 30" section, the "equalizer" taps into the side of the horizontal pipe.
The smaller boiler's riser(Boiler 2) goes up about 36" from the top of the boiler before turning at a 90, continues straight from there for about 24" before turning at another 90 and then about 3' before turning down into the common header. In the 36" section, the "equalizer" taps into the side of the vertical pipe.
The common header, from end to end goes in this order: HX feed, HX feed(NIU),HX feed, Boiler 1, Boiler 2, Building system main(mostly AHU coils and another HX), drip leg with F&T trap. That F&T trap goes down to a condensate pump that pumps into the feed tank. I've seen that condensate pump overflow quite a few times, also.
The problems I see with the piping are that the boilers don't really have individual headers before going to the common header. The equalizers aren't in a good position to catch carryover at a point where the direction of the steam will change. Additionally, the common header is set up wrong. The order should be as follows: Boiler 1, Boiler 2, load, load, load, load, drip trap.
I don't have much experience with boilers, so I'd like some input from some more qualified people. We also have our usual boiler/steam pipe contractor coming in tomorrow, and I plan on pointing these things out to him to get his opinion. Let me know if you have any questions.
Links of reading that I did to get me to this conclusion: