Guide for sizing the piping correctly in a hot water heating system when breaking up and adding zones?

Question

i own a huge building which has uneven heating. i want to break up some of the larger zones into several smaller ones, but i want to be sure to use the correct size pipes for supply and return for maximum efficiency. how can find out the correct size of pipes to use?

Answer 1

You haven't said whether you are using steam or circulating hot water, and what sort of radiators you have (baseboard, old fashioned cast iron, etc) Get the book "Pumping Away" by Dan Holohan.  Holohan also runs a website called http://www.heatinghelp.com/ where you can ask questions and order his books.

Holohan has good info on common problems like too-long runs of baseboard units and cost effective upgrades of older systems.  I learned lots from "pumping away."

I would be interested to know (assuming you have circulating hot water) if you are planning a reset control for the circulating water, staged multiple boilers, and more details about your zoning.