Any pointers?

That diagram is actually for the latest version of the Utica, not the Dunkirk. The Dunkirk manual, including the piping diagram, can be downloaded here:

http://www.dunkirk.com/products/boilers-gas/psb-series-ii

Note that on the page just before the diagrams, it says:

"8. Steam riser(s) and header shall be 2½” pipe size."

I would think this carries more weight than someone on the phone who may or may not be familiar with these units.

Ironman said:

I know it's from the Utica version: that was my point.

I've been involved with ECR and their engineering department for a long time - even to the point of being brought in to give input on the design of their mod/con. I wouldn't make the assumption that I can't get someone on the phone who knows their product.

Anyone who knows me or who's followed my posts knows that I always point them to what the install manual says. This was a rare exception and only after knowing that both boilers are the same product and consulting the engineering department.

In that case, how do they explain the discrepancy between the manual and what they told you on the phone? "that's the way it had always been" isn't what we need. There had to be a reason for specifying 2-1/2" pipe.

What I can tell you is that in our experience, these Dunkirk (and Utica) steamers do not like undersized piping at all. Every single time we've repiped one, it has worked much better.

So, how many of these boilers have you repiped, if any? And what were the results? ?

I taught HVAC at a local community college and we used the latest edition of the most popular, and best, hvac text book out there. I was told by my boss to teach from the text book without deviating too far from the information within those pages. That's when and where the problems between us began. There were errors in the text book that most people missed, including my boss, and he wanted me to teach that until I proved him wrong. I continued teaching what was true as I took my responsibility seriously. Luckily, the errors were corrected in subsequent editions.

My point is that is if you have BOTH the ability to read and a wealth of experience to go along with that, you're way ahead in the game. My boss had very little hands on experience compared to me and, as a result, he was teaching misinformation to students who were at his mercy. I refused to toe his line of what he believed to be truth just because he read it in a text book. So, over and over again, I was constantly forced to prove to him through other sources or real world experience (that I could prove in the lab) why I taught the way I taught.

Tim, my son-in-law, is constantly asking me why I do things the way I do things in a somewhat condenscending tone which bothers me to no end. My answer can sometimes be as short as just do it because I'm dialed in on getting the job done. It gives him time to think about it and he often has the "ahh" moment where nothing else needs to be said. But if it does, I'll tell him why and add that his entire 2 plus years of experience should not make him cocky.

My hands-on experience has taught me the hard way over and over and over again what works and what doesn't. It's a method of learning that hammers the truth home. I'm with Steamhead.

Bosses like that can be a PITA but they are the boss, hopefully he will learn it actually saves money to do it right the first time.

It might be worth showing the homeowner how to skim so they have some skin in the game, many are willing to do something like that once they understand what effects it can have on system operation.

Bob

It's always amazing to me how forgiving steam -- particularly if the pressures are kept right -- can be. Yes, there are better ways to do a lot of things, and sometimes even a best way, but... it's still amazing!

On the mismatched lengths on the swing joints -- it shouldn't make much difference. Maybe -- again -- not the best thing to do, but with relatively short pipe lengths, not to worry.