[trees]

I have the system up and working in my 40X60 shop. I use propane since we do not have natural gas available. Next fall, I hope to add solar panels to heat the water and use the propane as a back up. When I installed the system, we designed for the addition. We will install a reservoir to collect/hold the heated water from the panels for night time. It gets a little involved to drain the panels back into the reservoir at night so the panels do not freeze and to send it back to the panels the next day when the panel temp gets above the reservoir temp. I had this system in Utah and the panels work most every day, even with cloud cover and -15F outside temp. This winter, the thermostat has been set at 55* and I have been working in my shirt sleeves and the feet never get cold!! So far, I have burned 240 gal of propane. Not bad for heating 2400 sq feet and the heat has been on since mid Oct. Of course the mountains of North Carolina are not Canada in the winter time.

By the way, you did elevate the PEC to be in the middle of the slab thickness didn't you?

Trees

[Dave57210]

Yes we "lifted it" - the placing crew was VERY good - they had a "hook" that they used to lift the mesh-pex-rebar "sandwich" and poured concrete around it, let the mesh settle back onto the wet concrete, then let go and poured the rest of the concrete. The pex is approx 2" above the styro base everywhere now.

We put "Zip strips" into the concrete - they are thin plastic strips that function much like a cut through (but without cutting the Pex!) as "crackstops"

Because its indoors, we eventually decided not to use any expansion joints, but I DID leave a 1/2" gap around the edges. I did that by placing a half-inch thick border of styro 6 inches high above the styro "floor" to create a thermal "break" so that when I heat the floor, I am not heating the foundation as well. Ditto the need for a break between the shop floor and the approach slabs - I'm not trying to heat the whole world, and don't need the approach slabs in front of each door to be show and ice-free - I just want a warm floor!

Then when we (OK - my son did this part all himself) sprayed the "cure & seal" on the fresh floor, it dissolved the styro border. After the requisite 28 days, I will then go and caulk that "gap" so that little nuts, bolts, Carb jets etc, etc can't escape.

No drains and it's all dead flat level, set with laser levels, checked on a one-foot square grid as the placers and finishers worked.

[trees]

Sounds like you and your crew knew what you were doing!!! You are going to have a lot of visitors during the winter when they learn how cozy you are when the system is up and running. I put a big French drain in the middle of my shop because I like to mop up the dirty floor on occasion and I want to wash vehicles inside during the winter. It also takes care of the wet, drippy vehicles that I bring in, especially in the winter.

Trees

[speede5]

Nice floor. How many loops did you use, and how long per? I had three at 160+ ft per and the return was quite cool. Since I was using a conventional water heater it was pretty hard on the system. A boiler would have handled it easily.

I will be building a 30x60 or close in a year and will be heating the floor. It is such a great way to go.

I will consider your thermal barrier too. I heated the whole pad, glued 2" foam around the perimeter, but I could tell I was wasting heat. It was nise that the garage door never froze to the pad, but that extra bit of concrete outside was probably costing me a lot in wasted heat.

[Dave57210]

I have 3 zones - one used 7 loops, one used 3 and one used 4

All together there is about a half mile of PEX in there! (just over 2600 feet total!) The longest loop is 180 feet, the shortest is about 110. (hence the need for ball valves to "balance" things)

I posted a site in another section of HR.com about where to get info on laying it out.

Bottom line - you want 6 inches apart around the perimeter, and then a foot apart for the rest.

My son and I laid it all out and installed all the pex while trying to keep the lengths of all the loops as constant as possible

We also had to make allowances for my two 4-post hoists, so we had to mock up the hoists and mark the styro, then measure and make an accurate "map" for where the posts will be installed in a few weeks.

If U want the sites for how to lay it all out, I can dig 'em up & include them in here, or you can PM me

[keyswitch]

I have acess to a lot of waste oil Have any of you had experience with waste oil heaters? Like to hear from you. It gets cold up here in northern Ia.
Jim

[speede5]

Originally Posted by Dave57210

We also had to make allowances for my two 4-post hoists, so we had to mock up the hoists and mark the styro, then measure and make an accurate "map" for where the posts will be installed in a few weeks.

If U want the sites for how to lay it all out, I can dig 'em up & include them in here, or you can PM me

You can see where the post bases will end up, you sure were meticulous in your layout.

If you have some links that would be appreciated. I'll bookmark tham for future use.

Cheers

[Old Fool]

Great job!

What is the r factor of the foam you used?

When you get ready to run the system, cut the glycol back to 30 %, you will still have adequate freeze protection and have a higher heat transfer efficiency.
Check out Munchkin boilers.
Taco makes a good circuit setter for the money.
Make sure your expansion tank is for glycol and not for potable water

[Dave57210]

The sites I relied on for info on laying out the PEX tubing were:

http://www.houseneeds.com/shop/Heati...university.asp

http://www.radiantcompany.com/manual...l-Edition8.pdf

http://www.pages.drexel.edu/~mvj22/AED1/A5/hydronic.htm

I can't recall the exact R-factor of the styro I put in the floor, but it was 5 inches of Hi-Density (closed cell) styro, which I purchased at a local supplier of hydronic heating components. I remember that I looked up what the code called for (which turned out to be an R-factor of "whatever", which translated to four inches for this climate zone) and went 25% better. (I have an annoying tendency to over-build everything I do)

Then a bunch more research into "which type and brand of PEX is best" for this use - so far as I can tell, they are ALL good, but some are even better, although price is not a guide. The most expensive brand is not well-regarded by local installers. One brand kept coming up as "best", and I was told that it is NOT the red or white stuff, but is orange, so I went with that one. Add in a couple of bags (1,000 in each bag) of zip ties so you can attach the PEX to the mesh and/or rebar and allow at least 3 full days of messing around to get the layout exact - after you pour the concrete there are no second chances!

Fill 'em with anti-freeze/water mix, and start installing the couplings on the ends. When you have all the "cold" ends plugged and sealed, hit the "wearm ends" with 175 psi air and wait 5 - 10 minutes for any possible leaks to appear. No leaks? Good! Release the pressure, cap the hot end of THAT loop, and move on to the next one. If you DO find a leak (I didn't) then replace that whole loop! You do NOT want to have joints inside your concrete slab! (At least, I don't!)

[Old Fool]

Sounds like you may have used Nibco Barrier-Pex.

[Dave57210]

Any PEX you use for this has to be an Oxy-Barrier type.

I can't recall the brand off hand, but I'll go have a 'boo" at my "leftovers" because I am sure it has brand, type, etc on it

I just trotted out & looked - it was WATTS Radiant Pex that I installed.

[Old Fool]

Oxy Barrier pex is required if you have any ferrous metals in the system, which is almost a given.