Another header vs riser size thread

curiousburke_2

I know similar questions have been addressed many times before, but maybe not exactly this one.

I'm likely getting a Peerless 63-04L installed; the specification is for 2 2" risers into a 2.5"header. I want to step the header up to 3" and make it a drop header. That could be fed by 2 2" risers, but I think the tappings for the risers are 3", so I'm wondering if there is a disadvantage of using 2 3" risers, the same as the header.

I can see that having the same riser size will cause the steam to speed up in the header. However, the steam velocity in the header still wouldn't be any faster than with the 2" risers, would it? Is it the absolute steam velocity or the reduction in velocity that causes water to drop out?

Thanks in advance!

curiousburke_2

Thanks! I expected you to say I should put in a 4' header if I use 3" risers, and that using the same size was a no-no

curiousburke_2

If I went with 2 2" risers, it seems like the steam velocity is actually higher than 1 3" riser. Which is preferred?

And yet another question: I could have a 4" black iron header for about the cost of a 3" cast iron header (actually, less if it's imported iron) ... opinion?

New England SteamWorks

With that size boiler I would do it all in 3", including risers.

curiousburke_2

Thanks! All the possible configurations is really interesting to me. I would love to assemble the fittings myself, but don't feel like I could tackle some aspects of the job.

A little piece of me is still saying "get the SlantFin and 25 year warranty", and this 2x2" vs 1x3" issue raises that specter. I leaned away from SlantFin because of the single 2.5" riser; was that a poor deciding factor?

curiousburke_2

My EDR is 330 to 350, depending on this one radiator I've never been certain about, but then I have uninsulated mains in a basement that I like to stay warm. You estimated 390 including the main in my other thread.

With a 33% margin built in for average piping/pickup, I would think the 7% bigger GXHA-160 wouldn't make much of a deciding factor.