g1625s wrote:Yeah, he said 1 1/4 would be fine for my application. The kb8 is a serious boiler, probably meant for greater things than what I will use it for, but I have room to grow in the future when funds allow radiant in the floor.
I would use 1.25" for the supply/return piping and 1" for the bypass. 1.25" piping can move nearly the max capacity of the boiler at a reasonable supply/return differential.
If you want...run 2" from the supply tapping to the air scoop, then reduce to 1.25" after that. The larger pipe will "slow the flow" and the air scoop will be more effective. Not necessary, but a nice "twist" if you don't mind a few pieces of larger pipe.