gravity to forced , sizing.

Steamhead

going to install two boilers, or just keep the one? If the latter I'd just install thermostatic radiator valves in the tenants' area. This will let them control the heat in their rooms without overheating them.

If you're going with two separate boilers, check out Mike's response in the thread below. He handles this subject as well as I could.

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=28515&mc=2

kev

gravity to forced, sizing.

I am removing all of the gravity mains and leaving the risers in order to split the heating in a two family house. I have done this before with mono-flo loops, but in this case the risers are stubbed to far down to do properly. I plan to re-pipe with a two pipe system for each. The question is can I size the new forced mains by using the btu loads of each radiator? One zone has 6 rads with largest 6000 and smallest 2000 btu load.I want to be sure to flow to all rads, but not break the bank with large copper mains. I have ripped out plenty of 2 pipe systems, but never piped one from scratch and want it right the first time. Thanks for your response.

kev

Yes, there will be two boilers. I was thinking that if I reduced the size the feeds to the risers I could keep the system balanced. The supply would increase in size as I added radiators.

Steamhead

That would work

usually any hot-water radiator under 90 square feet EDR or so can be fed with 1/2-inch pipe.

Ron Schroeder_3

please do or have done

a real heatloss calculation for your home. Match your heat source and load to one another.