Pex for hot water heating system


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Old 12-29-09, 05:51 AM
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Pex for hot water heating system

I'm a little confused and have conflicting information. We have hot water heat with radiators. Everything works great, but in our basement the pipes that feed our radiators are hung very low (like five feet off the floor). We want to get them out of the way in order to use the space and not hit my head every other day. One plumber says these can be replaced with Pex tubing (not the same pex used for supply lines of course). The new Pex tubing would be routed up between the joists in the basement. Another plumber says you cannot use Pex, because the pipes need to have a slight grade/slant for the water to return to the boiler. Yet another says no, your furnace has a water pump and gravity is not an issue (as long as you don't go wild with how the Pex is laid out). Can someone with knowledge on this please help me understand what is accurate here.
 
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Old 12-29-09, 09:03 AM
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On a pumped system there is no need to slope the lines for the return of the water. Make sure the PEX used is barrier type (pex-al-pex or similar).

Al.
 
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Old 12-29-09, 09:42 AM
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Hi deke, I'm not a pro on this, but do you have a hot water heating system or a steam heating system? Steam may require a gravity retirn, but how water runs in a closed loop and can be run in circles. Provisions should be includes to drain low spots when service is required and the pex should be run according ly in that it drains to those low points, but otherwise, if you have a hot water system, the pex is fine. Just be sure to get your money's worth for the copper that gets removed. I have heard or plumbers commenting they would replace a homes copper with pex at no charge if they could keep the old copper. That may have been said at the peak of the copper prices, but the stuff in the stores is still rather expensive.

Bud
 
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Old 12-29-09, 11:56 AM
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Thanks guys. Yes, I have hot water, not steam. Also, my pipes are not copper, so I luck out there (I guess). I am adventurous, but this seems like a little out of my league as a DIY project. The one plumber quoted me quite a bit on this - close to $4k. I'm only do one part of the system. Say there is 20' of pipe (20' both ways) and connections to pipes leading to and from three radiators. I can see it being maybe two days of work so, something like 2k tops seems more reasonable. What do you think?
 
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Old 12-29-09, 12:26 PM
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I can see it being two days worth of work for someone such as yourself or me. But for a plumber I see a days worth of work.

You could possibly re-use the iron pipes and just raise them up. But you will likely get into cutting/re-threading and that will extend the project.

Since you have all Winter before this gets done look into how Pex is connected into systems. Along with what type of fittings are available for the radiator taps. Then make a list of what is required and when the weather gets warmer you'll be ready.

Al.
 
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Old 12-29-09, 02:59 PM
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Would be helpful to see some pictures of the boiler and near-boiler piping, and the piping in question. This might be an old gravity system, or a monoflow system, or something else. There could be pros, cons, and potentially "oh man don't do that" issues.
 
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Old 12-29-09, 04:38 PM
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Pictures would help...yes.

but this seems like a little out of my league as a DIY project.
If you have ANY doubts about it, don't even try. "A man's got to know his limitations".
 
 

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