2 pipe or 1 pipe risers.

Snowmelt

On a steam system what’s the advantage of 2 pipe instead of 1 pipe?
Also going to increase the manifold from 3 inch to 4 inch just so the water drops?
I hope I’m saying it right .

By the way it’s snowing here in jersey. My wife is not happy

Jamie Hall

Oh mercy. Well, there are things to be said for both systems with one pipe -- and for the variety of systems with two pipes. They both work well, if piped and sized and controlled right. They can both be miserable if not...

The advantage to making the header a size larger than the riser or risers is as you suspect to slow the steam down so that the water droplets -- which are inevitable but which you don't want -- can drop out. Going from 3 inch to 4 inch, for instance, cuts the velocity roughly in half.

Edit: on second thought you were asking about using one riser or two? Not the rest of the system? Well that's clear -- again, you cut the velocity in half, much drier steam. On bigger boilers there is an additional advantage, in that it helps keep the water level across the boiler more level.