Possible to reduce supply/return to Cast Iron radiators

James Beal

I currently have 3 cast iron ornate radiators, that I would like to reuse on a updated forced hot water system. My problem is the supply/return pipes are 2" black iron. I would like to reduce the size of the S/R to 3/4" in order to reduce the volume and demand on the current boiler. I would place these on a separate zone from the baseboard radiators in the other rooms, but have been getting varied answers whether the conversion will work. The cast iron radiators I believe were orginally steam, then converted to forced hot water. I like the style and they add historic flair to the building, although I understand they are less efficent then baseboard heat
Is this something that will work, or will I just be shooting myself in the foot? If, it can work, what are the critical factors that I need to be aware of? Any help on this would be greatly appreciated.

Sincerely
James Beal
B.D. Properties

John@Reliable_4

Maybe a easier way?

What if you added a flo-control to this part of system. This way you wouldn't have to repipe and would still be able to control the flow and the dumping of allot of cold return water. Hope this helps John@Reliable

J.C.A._3

How about...

Putting the radiators on a simple constant circulation circut , then control them with Thermostatic radiator valves ? If they have been holding water since the conversion,They're ok .

As far as being less efficient as baseboard, weigh the time spent heating , to the duration of heat retained, and my guess is that they aren't as inefficient as the perceived thinking. I love old radiators . Look at the heating curve on a graph basis, and you'll see that the baseboard looks like a pile of peaks and vallies, while high mass radiators graph looks more like a sign wave. The heat stays there longer with the mass, as opposed to dissapating quickly with low mass elements.

Being able to control the temp. in each individual area will make them all the more efficient. I say go for it .
Chris