Manifold for cast iron rads

otisopse

We are doing a re-pipe on an old mansion..the plumbing is just about done and now getting ready to re-pipe old heating..There are 12 cast iron rads..6 on each floor..existing pipe size to each rad ia 1 1/4,,would it be ok to use manifolds and if it is...what pipe size would work to each rad
and any thoughts on manufactures of manifolds//installing new boiler..Granby...The old system is daisy chained....Thanks

Jamie Hall

Need to know a bit more... I presume that this is a hot water system and not steam?

And by "daisy chain" I presume that a pipe feeds one radiator, and then the outlet from that one goes to the next radiator, and then the outlet from that goes to the next, and so on? And eventually gets back to the boiler?

You really have many options for putting in new piping, although the very first question I would ask is... do you even need new piping? But assuming that you do, the short answer to the question in the title is yes, you can use a manifold with cast iron radiators -- no problem. That is, assuming that you are thinking of piping each one individually from a central location, or dividing them up into several groups.

As to pipe size, you really have the cart before the horse. Obviously you could keep the present size and arrangement. However with individual or small group feeds, you really need to determine what the heat loss in each space is, and from that the temperature which will need to be supplied to each radiator to meet that heat loss and also the flow to that radiator to meet the heat loss. Then you can figure the pipe size (and, from the temperature, the material).

JohnNY

I think this old mansion needs someone to design a heating system for it and specify all the stuff on paper.

Jamie Hall

JohnNY said:

I think this old mansion needs someone to design a heating system for it and specify all the stuff on paper.

Totally agree... I wonder if the OP is DIY or the contractor?