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Replacement pipe for hot water heat?

11K views 18 replies 3 participants last post by  Tmb9862 
#1 ·
We're considering finishing the basement. Heat in this house though was an after-thought. The boiler is in the middle of the biggest room in the basement, and the pipes hang low enough you need to duck.

The heat is hot water with cast iron radiators. Currently the system is a combination of copper pipe and galvanized pipe. The radiators that have been added on use 3/4 or 1/2in copper pipe. Copper pipe I can work with and raise up to where it has to be so those arn't a problem. Unfortunatly copper is in the minority. The older radiators use galvanized pipe about 2.5in which I can not work with.

What are my options? I'd really rather not replace all the galvanized pipe. The pipe is exposed where it goes around the radiators so I want to leave that as galvanized for sure. I'd like to adapt from what I'm useing to the galvanized pipe where it runs up the wall. So what can I use? To the best of my knowlage this is what's available to me:
Copper - Should work fine but will be very expensive
PVC - Not for heating systems
Galvanized - Will work but I can't work with it
Pex - Biggest diameter I've seen is 3/4. Do I need to stay with the 2.5in current size or can I downsize?
 
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#3 · (Edited)
It is one zone, just very oddly plumbed. Extension added on, extra radiators tacked on, heat added to basement, etc. A lot of extra pipe that could be done away with.
It is definatly a hot water boiler.
So copper is the only solution? I guess I need to go with the 2.5in pipe then right? 2.5in copper pipe would probably run me $1000 in materials. That will hurt but still be a hell of a lot cheaper than paying someone to work with the iron.
 
#5 · (Edited)
I am certain it's a hot water boiler.

That is the circulator, correct?
When I bleed the radiators hot water comes out.

I was wrong about the 2.5in pipe though. 2in pipe goes into and comes out of the circulator. Then the 2.5in pipe forks, after the fork it steps up to 3in pipe. You can see the half inch copper pipe in the picture for an added radiator. The pipes then have another series of un-necessary forks.


The heat has been converted from coal - oil - gas.
 
#10 · (Edited)
They use two pipes. One on one side, another on the other.

yes this is difently a hot water boiler.When I look at your pipping system it appears that your system originaly was a steam system that was converted.you can use 1 1/4 copper,or galvanized piping.my prefrence is copper easier and faster to work with.The old pipes were so large because it was a steam system.With hot water you dont need such big pipping.
Another factor though is I want to keep the pipes inside the walls. These pipes are two to two and a half inches. Seeing as how these pipes would still exist would the new copper need to be larger to provide the extra volume?
 
#9 ·
yes this is difently a hot water boiler.When I look at your pipping system it appears that your system originaly was a steam system that was converted.you can use 1 1/4 copper,or galvanized piping.my prefrence is copper easier and faster to work with.The old pipes were so large because it was a steam system.With hot water you dont need such big pipping.
 
#12 ·
Sorry for not being clear enough before. The original galvanized pipes are already in the walls. I want to utalize those pipes and only replace the ones in the basement. The ones already in the wall that I will be useing are 2in - 2.5in. So my question is is it alright to go from a 1 1/4 copper pipe to a 2.5in galvanized pipe.
 
#16 ·
You're correct their is one loop. The one loop has what I'm going to refer to as sub-loops comming off of it (radiators that were added on).

As far as adding multible zones the house warms up pretty evenly and is comfortable.
The only thing I'm considering is makeing two loops, of rather one main loops and the kind of a sub-loop I described before for an attached apartment.. I'm contemplating installing a second boiler and that would make any future install easier. I'm hesitent to give him his own zone as I know he'll run the thermostat around 75 degrees and tack an extra $100 a month onto the gas bill
 
#19 ·
I havn't done any work yet but I now know I can use 1-1/4 copper, so yes I suppose that problem is solved.
The work itself is going to wait for the summer. The pipes are 80 years old, if they want to start breaking in the walls when I touch them I want it to happen when I don't need the heat.

Thanks to everyone for the help.
 
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