Old Loop System

Big Ed_4

Unless you live in a turn of the last century mansion. What you have is a old gravity system. They did not use cirulators. You can hook it up into a parrell system using a cirulator. You want to connect the branch piping reverse return. It go like this. First supply branch out will be the last to to return on each manifold.

Scottr6

removing old cast iron pipes on heating system

Hi, I'm hoping someone may be able to help me think through my heating pipe project in my basement. I'm renovating my basement and wanted to hide the heating pipes that feed my second floor heat up between the joist. I have hot water old cast iron radiators up on the second floor that are fed by a large 3" cast iron pipe that has 1" pipes which branch out to feed each radiator. The return is the same scenario. A second cast iron pipe with branches feeding in for the return back to the boiler. I wanted to get rid of the large cast iron pipes and feed these individual branches from a central manifold back at the boiler using cooper or pex running separate supply and return lines for each branch that was originally supplied by the cast iron pipe. I envision two manifolds, 1 supply 1 return. Is this possible? I'm guessing the cast iron pipe was so huge to insure enough hot water made it to the last radiator but I would hope the new design would still meet this need. any help provided would be greatly appreciated.
Thanks

Alan(OnVacationInOregon)Forbes

And yes,

you can pipe it with a reverse return system like Big Ed says or you can do it the way you suggest, with separate loops to each radiator from a central manifold.

Scottr6

Thanks for the info.
Is it a gravity system if I have circulator pumps at the boiler? The oil boiler was replaced about 5 years ago from the old stone age one that was down there. Was thinking about switching over to the on demand gas heaters when my gas water heater dies but don't know if its worth it. The oil boiler has an 85% effeciency rating.
When using the manifolds, whats the best size pipe to run for each loop? Thanks again for all the advice.

Alan(OnVacationInOregon)Forbes

If you have a pump,

it's a pumped system; with no pump, it's a gravity system.

Piping to the radiators: normally 1/2", but you could use 3/8" as long as the radiators are smaller than 1,200 BTU output.