ci rad conversion

BOB_22

When converting thin tube rads from steam to hot water, I'm a little confused on the piping into and out of the rad. In Dan's book "How Come", it says to enter and leave the rad from the bottom (although this is in the diverter tee section, and I'm not piping that way). In his article on converting, it says to enter the rad from the bottom and leave from the top. The third change I saw was in the HVAC.com section where Dave converted a system and it looked like he entered from the top and exited from the bottom,although this may have been an old gravity job. Does it matter which way you pipe, and if so can anyone explain why? Thanks for the help.

Mike T., Swampeast MO

Iron rads have such large internal passages that unless you're moving an extreme volume of water at extreme velocity, the flow (and heat) tend to distribute quite evenly regardless of whether you use bottom-bottom or top-bottom connections. Just don't use top-bottom on the same side unless you have the special tapping with a pipe that extends to the other side of the rad.

If you're using TRVs and can manage, it's nice to put the supply on the top and return opposite side bottom. It's a good place to read room temperature and more convenient to operate.

Bob_36

Thanks for the info. I thought that it might work either way, but the heat might be distributed better in a certain set-up.

Weezbo

Hello.

it indeed matters ,the larger pannels i think wont produce what you think they should ,it is the same thing with like a car radiator. you would notice it really clearly in super cold conditions ....think of it this way if you had a bucket of water and wanted to heat it uniformly where would you want the taps to be? now think of a really large sized window with water flowing in and out of it in the best case you would designe inside the window lots of little holes along one side and the same with the other so youd get more uniform distribution. if both the supply and return entered from the bottom on opposite sides the flow of waster would want to cruise straight accross to the other side ,so you would end up with cold spots in the radiant window.same thing happens in a radiator basically.
true it produces heat ,just maybe has cold spots and not the best of distribution . a modine radiator guy could make a whys and wherefore picture on a graph...i am not too good at drawing a computer picture,or posting one.

Bob_36

WATER FLOW -WHICH WAY

So I assume you're saying in at the bottom and out of the top? Or is the opposite a better way to go? I'm trying to visualize the water going in, and as it does, the hotter water is rising to the top. So is it beter to let the water in from the top and as it is forced to the bottom, the hotter water is rising, or come in from the bottom, and as all the water rises, it all starts to heat up?

Weezbo

Bob. there is a site linked to here PM....

you can go there and look for the topic at hand and they disscuss every aspect of this topic. i see if i can find it right quick for you.has pictures:)

Bob_36

ci rads-PM


What sight are you referring to? What is PM(other than afternoon)? Sounds like it could be helpful. I finally got out all the plugs top and bottom. What a job. So now I can start planning my piping layout. Looking forward to your info.











what

Weezbo

look at kals message to hot rod in the topic possibly my ...

biggest job. here is an excerpt from an artical printed some time ago on the subject of flows thru pannel radiators... look at the Blue pictures...there are 4. all "work" however at least you can see your best shot with the system you currently have and if you need to make a change or two to maximize the output you will at least have some Reason as to specifically what you want to do and how you will have to modify it to do exactly what you want it to do:) thank the guys for helping oneanother your question was answered by someone helping someone else:) dang near contageious init?:)