Hot water BTU rating for cast iron radiators

PG

We have a chart and directions for figuring EDR, or the steam btu output. Is there a way to convert that to find the out put when hot water is in them?

PG

Cast iron radiators for hot water?

I'm renovating a couple of rooms that used to have electric baseboard, that used to have steam heat (old steam lines are buried in a slab, I don't want to mess with these). The rest of the house has 2 pipe steam. Can I keep the same look (use the same type of rads?) with hot water heat? I'd like to add a small hot water boiler with 2 zones......what do you think? My heating pro says no problem but I just want to make sure we're doing the right thing. I have one old radiator in the garage, and also found a supplier of used rads (they pressure test them first). I need approximately 20,000 BTU's per room. How do I figure out the output of these rads with hot water? Thanks for any insight!

Timco

I've seen that done, but each section of the rad...assuming the rads are steam rads to begin with (a common pipe at the bottom only) had to be tapped and a bleeder valve installed to be able to bleed it. Then they got hot as any rad ever. If the rads have a low and high pipe, they are dual use and you just need to get the plug out for the bleeder valve and plug the steam vent plug. There are books that tell you the square inches or square feet of heating surface of a make of rad, and depending on that and the degree of water in them, you get your btu's.

T

Bob W._3

Wouldn't his 2 pipe steam rads normally be the dual manifold type? My one pipe rads are mostly single manifold.

J.C.A._3

Dan's EDR book,

Has a chart that gives output per sq.ft. of edr @ different temps. Chris

J.C.A._3

Dan's EDR book,

Has a chart that gives output per sq.ft. of edr @ different temps. Chris

J.C.A._3

Dan's EDR book,

Has a chart that gives output per sq.ft. of edr @ different temps. Chris

Sorry for the triple post!

PG

Sorry I don't have the book......yet. Does someone know the conversion formula to go from from steam to say 170 degrees hot water?

PG

Radiators

The one I have and the ones I'm looking at purchasing have openings at the bottom on both sides. There is a plug (small) near the top that the supplier said they can remove for a vent. Also they are connected at the top, supplier says they are right for hot water.

Bob W._3

I would have tried the same conversion but mine are mostly single manifold - connected at the bottom. Good luck.

Bob W._3

Also, have you read Dan's article on Hot Tech Topics, re: converting steam to HW?

http://www.heatinghelp.com/newsletter.cfm?Id=22

In there he states you will get 150BTU/sq. ft. of radiation using HW instead of steam.

Guy_6

TRV

I would install TRVs on the radiators from the get go. It will allow you great control over the output .