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Hydronic heating system

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Wolvenar:
This will certainly be a post that is ever changing

I have been working on hydronic heating our house. We have it partially done,

Latest addition.

We have a 1950's build house, with a full concrete basement. We really wanted to get the floor heating done in our bedroom but being this is winter it would be next to impossible to pull the concrete up and replace with the same. So for the meantime I just added a wooden floor on top of the current concrete, Maybe some day we will redo this in concrete to get the added heat storage but for the foreseeable future, this will work





Beginning of (over)building the boiler (sorry some images are not so good)


Starting with the cut material



Stacked to test that it all fits, nothing welded.
Now to grind each edge to create a v shape to weld into, and generally clean the
area to weld




First weld.



Second chamber of four.



Another view

More to come, I need to find more pics, and tale some of it finished
 

philb:
Hi Wolvenar,

i'm glad to see a post on Hydronic heating systems. That makes good sense.

How far apart are the pex tubes?

I don't have a lot of experience here. but my neighbor, the house builder does. He told me to put two strands together, 6 inches apart. He has had complaints with people saying one area is warm, while next to that, it's cold. If one tube leaks in the future,  switch to the second.

A hot water heater is his heat source. For a 5000 sq ft house, it costs $150.00/ month to heat it.



Laminate floor might be a good choice here.

rossw:
Wolv, got a couple of suggestions/questions.

I've seen some people nowdays retrofitting hydronics to concrete slabs by laying the pipe directly on the old slab and fixing it, then pouring a very runny slurry of concrete over it. It's self-leveling, makes a lovely smooth finish, beds the hydronics in and couples it to the old slab (if that's your wish, otherwise foam under it I guess), makes it a fairly thin skim, and gives you some thermal mass.

Also, I'm surprised you have coils crossing over each other. That was always an absolute no-no in my circles. Running a double-spiral gives you a number of advantages. Start and end come out together, you don't have to cross over any pipes so it's all low and flat and you never kink or crush a pipe, and you have alternate hot/cold pipes. Not really "cold", but "flow" and "return". So at the "feed" end where the hottest water is, is balanced out by the last of the return water beside it - so it "averages" out. At the centre of the coil (in the middle) the return water is warmest, and the hot water is coolest...  I'll find a photo if you like.

I too thought you may have put the pipes a little closer together...

Wolvenar:
Ross, why does it not surprise me that you are the first one to notice or mention the touching PEX.
Since this floor was built to be temporary, when the kids move out that room will be doubling in size again.
This was a remodel to add another room for our youngest who is now getting old enough to need one (leaving us in a smaller room)
So this truly is one of two experiments I have going to prove one way or another if there is truth behind the warnings.
Though it might not live long enough to be definitive since there will be another remodel in only a couple decades if destiny permits.

 I was told about never crossing (we briefly discussed it in IRC once also), I've also been told exactly  opposite "it does not matter by" very experienced contractors.  I have seen at least 4 systems set in concrete put together in the 80's that are touching/overlapping at many points in the system with no failures so far.  I tried to find reasoning for this, but there again I had no real definitive answers. The best answers I got were:
The system builds and electrical differential from the hotter and colder sides of the loops, and creates an electrical field that will break down the aluminum oxygen barrier where ever the is close contact. Another answer was as simple as: you lose efficiency as the heat transfers at each contact/near contact point. Yet another answer was that the loops cannot touch in concrete because it causes thermal stress points that damage the concrete in a short time.
 To me the second answer is debatable on the amount of efficiency losses because any which way the heat stays in the system. Secondly there are not that large of contact points if that is the true reason. Now as for the first I cannot say for sure given the way the aluminum is embedded in between layers of the PEX  plus each end of the loop is grounded to the manifolds.  This floor was from the beginning built as a quick fix meant to last however long it lasts. So I intentionally crossed and made points that are even zip tied together as I consider this a long term experiment. I have a concrete walk in front out our porch that next year I will be embedding PEX into to save my back some shoveling  grief. I plan to place PEX with several contact points with the same idea. This may or may not work out well to make a conclusion on all three theories given these are all circumstances covered between the two setups / wood concrete. In doing this I'll also answer my question on if it matters where the PEX is. The harsh temperature changes as its turned on raising from (normal) Mn cold to melting point should hasten the results.

Wolvenar:

--- Quote ---How far apart are the pex tubes?
--- End quote ---

This is mostly 16in on center, though I had to fudge a little in a couple places, the part of the room you see it more like 18. I added more shorter pieces crosswise before I put down the top than is shown in this pic.

If I were to put in concrete I generally have a pipe no farther than every 12in as per any contractor n my areas recommendation. I don't know if this spacing has anything to do with how warm or cold your climate is, or if its to be sure of even heating.


--- Quote ---A hot water heater is his heat source. For a 5000 sq ft house, it costs $150.00/ month to heat it.
--- End quote ---
I have seen this done A LOT around here. Its cheap, but unfortunately a lot more work if and when an element fails as there is a lot more drain down.
I (over)built my own electric boiler, I'll post more on it here later.

--- Quote ---Laminate floor might be a good choice here.
--- End quote ---

Oh yeah also, even as this would likely be considered to far spaced piping, ie to few feet of PEX it's way more than enough for this room. The walls are now VERY well insulated. and upstairs of course is heated also.

We found a deal on linoleum that we could not pass up, and since this is temporary...
 

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