Header sizing

Dave0176

On that WM EG30 boiler I'm installing, should I run two 2" risers into a 3" header. Or should I size it to a 2 1/2" header.

Paul S_3

manufacture

What does the manufacture say?I usually use the size the manufacture states for the risers and I go up a inch for the header...for example of it says 3 inch header I use 4 inch Paul S

JStar

Header

****Header Size per Maximum BTUH Output****

(Based on Velocity of 15 ft/sec. to 20 ft/sec.)

2" Header = 48,384 - 64,512

2.5" Header = 68,832 - 91,776

3" Header = 106,416 - 141,888

4" Header = 183,312 - 244,416

5" Header = 287,856 - 383,808

6" Header = 416,016 - 544,688

Dave0176

Thanks Jstar

I seen that chart, but I also seen 3&4 section boiler 3" header 5&6 section boilers 4" header??? Should I run at least a 2 1/2 header??