DIY Hydronic Floor Heating - Page 14

pachai · 06-29-11, 02:58 PM

I have a picture to post.
Not my work. The contractor wanted the plumber to do it.
The plumber's son is a great listener, did just what I requested....

http://pachai.net/gshp/Floor_loops_enter_floor.jpg

Ko_deZ · 06-29-11, 03:05 PM

That could not have been done better

AC_Hacker · 07-01-11, 10:38 AM

Here is a diagram of a PEX spiral arrangement that Ko_deZ was describing previously.

I believe that Ko_deZ was describing a single spiral, this one has three tubes, same idea for the pattern.

-AC_Hacker

pachai · 07-01-11, 11:55 AM

I saw that I had another day or so to perfect the radiant floor before the cement is poured....so I called my friend to ask about embedding temperature probes in the cement. I know he has them, they are just a 3-pin chip.

He had a better idea....
I bought 10' of 3/8" copper tubing and cut a few 8" lengths.
One end of each 8" length, I put flux in and on, flattened and folded it over, then soldered it shut. After I did a few, I added a piece of copper ground wire to use for stapling.

Click image for larger version

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The open end goes through the floor to the basement.
Now, we can decide what kind of temperature probe to use.
It just has to fit in a 3/8" tube.

Click image for larger version

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THAT will integrate well into my friend's steam management system (will need to change the name). When a room is cold, you DON't need heat on until the ROOM is warm. You need heat on until...the radiator is hot. Then shut off the boiler (or the circulating pump) until the radiator gives up its heat to the room. Then check your cycle rules and turn on again.

(The picture here is actually the last one installed, as the tile guy was coming up the stairs, I realized I had time to do one more if I didn't need to drill...and there was one place where I could get into the wall cavity...

I tried to put one sensor tube at the far end of each loop, so I'll have temperature readings "entering" the floor, "leaving the floor" and halfway around. There are 4 loops altogether, 2 under the kitchen area and 2 under the breakfast nook. I don't think they will have separate thermostats, but separate mixing valves.

I still did not figure out where to get cheap pumps,
though I was thinking I could (theoretically) get this
working tomorrow by getting one of those "hot water recirculating pump" - it pulls hot water and ships it back down the cold line until the water is hot.
I see these are available for around $150...
but they might not be the best for our purposes.

I am thinking of having a pump for each zone or each loop,
depending how expensive they are.....
or alternatively, a pump for each floor, and VALVEs to control where the water goes.

Any suggestions welcomed.

pachai · 07-01-11, 12:09 PM

The one issue of hiring a "trade professional" who does similar work, rather than one in the specific field, (or DIY who reads the literature), is they (think they) "know how to do it!"

I told the plumber to make sure he doesn't run out
in the middle of a circuit. He said he has splices.

I told him NO SPLICES IN CEMENT.
The splices WILL fail someday, and I'll have to
break the tiles.

So he listened to the important part....
but he did use 2 splices under the subfloor....

Click image for larger version

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ID: 1589

pachai · 07-03-11, 01:35 AM

The next topic that is starting to get to its turn at the front of the line is....
How to add radiant floors to an existing house?

When the contractor happened to demolish the
ceiling in the old kitchen, I did the "midnite
plumber" thing and put a staple-up for the
one small room above. I routed those pipes
back down to the basement for future access.
Drywall is up, and pressure holds at 48psi.

Now I am looking at putting similar loops
in places that are not (yet) accessible.

I have thought of a few options.
Our house has a center 6' wide corridor,
with 2 load-bearing walls, and
12' wide rooms on either side...
Due to a flooded bathtub, the ceiling
in this hall came down. I screwed up some
luan to make it pretty for my mom until I
get to take advantage...for wiring, etc...
(or radiant floors :-)

I am trying to figure out if breaking all the
other ceilings is the only way to put in
radiant heat. Would it suffice to remove a
narrow band of ceiling and use my broken
hallway ceiling for access?

My question is, would a 1/2" pex somewhere
in an 8" joist cavity do me any good at all?
I have some experience fishing 12/2 wire,
but 1/2" pex is not the same...

I could try to figure out how to make
and deploy some "trestles" to hold
the pex up close to the subfloor, but
probably can't get it all the way....and
mustn't forget the nails that come down.

Oh, I just realized...
there is a decorative wood "skirt" around
my house....and I know from insulating
experience, that these are hollow,
and open into the wall cavity.
So that means, I might get access to
the far end of the joist cavity...from outside
my house. But again, is it enough to
just have a pex in a cavity?

Thanks
Seth

Ko_deZ · 07-03-11, 04:14 AM

No, that would not do much good i'm afraid. To transfer heat to a wooden floor (or anything but a solid concrete one), you need physical contact. The best way is to use heat spreader plates so that the thermal energy from the pex is spread across a larger area. The stapling does work to some extent, but it is not very efficient, and you get uneven temperature as only the wood just above and around the tube is. Also you need a higher temperature to get enough energy transferred to the floor. If there is something like 2 inches of wood between the pex and the top of the floor, the thermal conductivity would call for even higher temperatures of the water (which reduces COP).
The best way of doing this is not pulling the ceiling down, but building your floor up, or replacing the top layers of it. Then you can place heat spread plates and you final wood layer straight on top of those.

pachai · 07-04-11, 01:32 AM

Ko_deZ,
Thanks. I was trying to save the oak floors.
(They are original, circa 1929 :-)
Other options include
1. forced air - I plan to use a MultiAqua air handler
for summer A/C, and it can be used for heat in the winter, but I think radiant is better.
2. Radiant walls. I saw this mentioned in
another thread. Not as good as floors.
3. Designing a spreader that can be deployed "orthroscopically"

Thanks again.
Seth

AC_Hacker · 07-04-11, 12:58 PM

Quote:

Originally Posted by pachai

Thanks. I was trying to save the oak floors.
(They are original, circa 1929 :-)
Other options include
1. forced air - I plan to use a MultiAqua air handler
for summer A/C, and it can be used for heat in the winter, but I think radiant is better.
2. Radiant walls. I saw this mentioned in
another thread. Not as good as floors.
3. Designing a spreader that can be deployed "orthroscopically"

Pachai,

A couple of days ago, I downloaded the Watts Radiant design program, RadiantWorks Pro ... very interesting... and free for 30 days anyway, perhaps longer.

My weather environment is much milder than yours, and I have become pretty obsessive about insulation, and I was checking out my radiant heating test room (12' x 12') that I hope to get built this summer, using the above program.

Here are some feed temperatures that the program calculated for me, using various radiant heating schemes. The program is limited to the schemes that feature products that Watts Radiant sells (no surprise), but it is instructive, nonetheless.

Quote:

Slab - 86.4
Thin Slab - 85.5F
Sandwich Over Slab - 96.6F
Sandwich over floor - 96.6F
Under Floor - 93F
SubRay Over Slab - 100.6F
SubRay Over Floor - 100.5F

[NOTE-1: SubRay seems to be a pre-fab version of what Vlad built in his house, minus the spreader plates.]

[NOTE-2: None of the schemes seem to use spreader plates, even though Watts Radiant sells a thing called 'Flex-Plate' that is made of carbon graphite fiber and small aluminum spreaders... looks really great and really expensive.]

You shouldn't let the temperatures suggest anything to you, but the percentage differences might well be of interest.

RadiantWorks Pro is available on this page.

Best Regards,

-AC_Hacker

webaware · 07-15-11, 07:17 PM

Hi to you all!
I've read some of this thread and some of the heat pump manifesto thread (thank you for your great effort AC Hacker).
I'd like to share my experience of using steel roof cladding as radiant panel.
The story so far:
I'm building a two storey extension to my house (45m2 per storey). I've installed ~100m of 15mm PEX in 50mm concrete screed on the ground floor. That's all fairly standard, but I wanted to put radiant underfloor heating upstairs. To cut to the chase, I've placed roof cladding upside down, on top of the joists. In the UK, joists are normally at 400mm centres, and the ridges in cladding are at 200mm centres, so if you flip the cladding panel upside down, you get two channels about 30mm deep, and between 120mm and 80mm wide.
I fixed the PEX to the channel with cable ties through which I screwed a self-tapping screw. I grouted the pipes into the channels with a weak sand/cement mortar (10:1). The cement's really just to stop the sand shaking out, and needs no strength.
I've tested the three upstairs circuits under water-mains pressure - all good.
The intention in the short term is to connect all the underfloor circuits to our oil-fired central heating (via a temperature regulating manifold) in the longer term (next spring - after i've finished the extension).
Anyway, here's some pictures of the job so far.
Cheers
Tim (webaware)

06-29-11, 02:58 PM	#131
pachai Renovator-in-planning Join Date: Oct 2010 Location: Northern NJ Posts: 85 Thanks: 6 Thanked 0 Times in 0 Posts	I have a picture to post. Not my work. The contractor wanted the plumber to do it. The plumber's son is a great listener, did just what I requested.... http://pachai.net/gshp/Floor_loops_enter_floor.jpg Last edited by Daox; 11-17-11 at 02:57 PM..

07-01-11, 10:38 AM	#133
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	Here is a diagram of a PEX spiral arrangement that Ko_deZ was describing previously. I believe that Ko_deZ was describing a single spiral, this one has three tubes, same idea for the pattern. -AC_Hacker Attached Thumbnails __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker...

07-01-11, 11:55 AM	#134
pachai Renovator-in-planning Join Date: Oct 2010 Location: Northern NJ Posts: 85 Thanks: 6 Thanked 0 Times in 0 Posts	Radiant Floor Sensors I saw that I had another day or so to perfect the radiant floor before the cement is poured....so I called my friend to ask about embedding temperature probes in the cement. I know he has them, they are just a 3-pin chip. He had a better idea.... I bought 10' of 3/8" copper tubing and cut a few 8" lengths. One end of each 8" length, I put flux in and on, flattened and folded it over, then soldered it shut. After I did a few, I added a piece of copper ground wire to use for stapling. The open end goes through the floor to the basement. Now, we can decide what kind of temperature probe to use. It just has to fit in a 3/8" tube. THAT will integrate well into my friend's steam management system (will need to change the name). When a room is cold, you DON't need heat on until the ROOM is warm. You need heat on until...the radiator is hot. Then shut off the boiler (or the circulating pump) until the radiator gives up its heat to the room. Then check your cycle rules and turn on again. (The picture here is actually the last one installed, as the tile guy was coming up the stairs, I realized I had time to do one more if I didn't need to drill...and there was one place where I could get into the wall cavity... I tried to put one sensor tube at the far end of each loop, so I'll have temperature readings "entering" the floor, "leaving the floor" and halfway around. There are 4 loops altogether, 2 under the kitchen area and 2 under the breakfast nook. I don't think they will have separate thermostats, but separate mixing valves. I still did not figure out where to get cheap pumps, though I was thinking I could (theoretically) get this working tomorrow by getting one of those "hot water recirculating pump" - it pulls hot water and ships it back down the cold line until the water is hot. I see these are available for around $150... but they might not be the best for our purposes. I am thinking of having a pump for each zone or each loop, depending how expensive they are..... or alternatively, a pump for each floor, and VALVEs to control where the water goes. Any suggestions welcomed.

07-01-11, 12:09 PM	#135
pachai Renovator-in-planning Join Date: Oct 2010 Location: Northern NJ Posts: 85 Thanks: 6 Thanked 0 Times in 0 Posts	Splices! The one issue of hiring a "trade professional" who does similar work, rather than one in the specific field, (or DIY who reads the literature), is they (think they) "know how to do it!" I told the plumber to make sure he doesn't run out in the middle of a circuit. He said he has splices. I told him NO SPLICES IN CEMENT. The splices WILL fail someday, and I'll have to break the tiles. So he listened to the important part.... but he did use 2 splices under the subfloor....

07-03-11, 01:35 AM	#136
pachai Renovator-in-planning Join Date: Oct 2010 Location: Northern NJ Posts: 85 Thanks: 6 Thanked 0 Times in 0 Posts	Radiant tubes in "old work" The next topic that is starting to get to its turn at the front of the line is.... How to add radiant floors to an existing house? When the contractor happened to demolish the ceiling in the old kitchen, I did the "midnite plumber" thing and put a staple-up for the one small room above. I routed those pipes back down to the basement for future access. Drywall is up, and pressure holds at 48psi. Now I am looking at putting similar loops in places that are not (yet) accessible. I have thought of a few options. Our house has a center 6' wide corridor, with 2 load-bearing walls, and 12' wide rooms on either side... Due to a flooded bathtub, the ceiling in this hall came down. I screwed up some luan to make it pretty for my mom until I get to take advantage...for wiring, etc... (or radiant floors :-) I am trying to figure out if breaking all the other ceilings is the only way to put in radiant heat. Would it suffice to remove a narrow band of ceiling and use my broken hallway ceiling for access? My question is, would a 1/2" pex somewhere in an 8" joist cavity do me any good at all? I have some experience fishing 12/2 wire, but 1/2" pex is not the same... I could try to figure out how to make and deploy some "trestles" to hold the pex up close to the subfloor, but probably can't get it all the way....and mustn't forget the nails that come down. Oh, I just realized... there is a decorative wood "skirt" around my house....and I know from insulating experience, that these are hollow, and open into the wall cavity. So that means, I might get access to the far end of the joist cavity...from outside my house. But again, is it enough to just have a pex in a cavity? Thanks Seth Last edited by pachai; 07-03-11 at 01:38 AM..

06-29-11, 03:05 PM	#132
Ko_deZ Helper EcoRenovator Join Date: Jun 2011 Location: Norway Posts: 63 Thanks: 3 Thanked 10 Times in 10 Posts	That could not have been done better

07-03-11, 04:14 AM	#137
Ko_deZ Helper EcoRenovator Join Date: Jun 2011 Location: Norway Posts: 63 Thanks: 3 Thanked 10 Times in 10 Posts	No, that would not do much good i'm afraid. To transfer heat to a wooden floor (or anything but a solid concrete one), you need physical contact. The best way is to use heat spreader plates so that the thermal energy from the pex is spread across a larger area. The stapling does work to some extent, but it is not very efficient, and you get uneven temperature as only the wood just above and around the tube is. Also you need a higher temperature to get enough energy transferred to the floor. If there is something like 2 inches of wood between the pex and the top of the floor, the thermal conductivity would call for even higher temperatures of the water (which reduces COP). The best way of doing this is not pulling the ceiling down, but building your floor up, or replacing the top layers of it. Then you can place heat spread plates and you final wood layer straight on top of those.

07-04-11, 01:32 AM	#138
pachai Renovator-in-planning Join Date: Oct 2010 Location: Northern NJ Posts: 85 Thanks: 6 Thanked 0 Times in 0 Posts	Ko_deZ, Thanks. I was trying to save the oak floors. (They are original, circa 1929 :-) Other options include 1. forced air - I plan to use a MultiAqua air handler for summer A/C, and it can be used for heat in the winter, but I think radiant is better. 2. Radiant walls. I saw this mentioned in another thread. Not as good as floors. 3. Designing a spreader that can be deployed "orthroscopically" Thanks again. Seth

07-15-11, 07:17 PM	#140
webaware Lurking Renovator Join Date: Mar 2011 Location: wales, uk Posts: 9 Thanks: 6 Thanked 0 Times in 0 Posts	radiant panels from steel roof cladding Hi to you all! I've read some of this thread and some of the heat pump manifesto thread (thank you for your great effort AC Hacker). I'd like to share my experience of using steel roof cladding as radiant panel. The story so far: I'm building a two storey extension to my house (45m2 per storey). I've installed ~100m of 15mm PEX in 50mm concrete screed on the ground floor. That's all fairly standard, but I wanted to put radiant underfloor heating upstairs. To cut to the chase, I've placed roof cladding upside down, on top of the joists. In the UK, joists are normally at 400mm centres, and the ridges in cladding are at 200mm centres, so if you flip the cladding panel upside down, you get two channels about 30mm deep, and between 120mm and 80mm wide. I fixed the PEX to the channel with cable ties through which I screwed a self-tapping screw. I grouted the pipes into the channels with a weak sand/cement mortar (10:1). The cement's really just to stop the sand shaking out, and needs no strength. I've tested the three upstairs circuits under water-mains pressure - all good. The intention in the short term is to connect all the underfloor circuits to our oil-fired central heating (via a temperature regulating manifold) in the longer term (next spring - after i've finished the extension). Anyway, here's some pictures of the job so far. Cheers Tim (webaware)