Radiant floor heat design

[ScottFJ40]

Does anyone who has radiant in floorheating have any plans or designs? I want to put this together myself, but I want to make sure it's done right.

[fordnut]

a friend of mine just built a garage with radiant heat it was a plastic hose type of material specific for radiant of course, he just laid it out in the spacing acording to directions that came with product and tied it in to a seperate zone on his furnace. seemed very simple and user friendly and its nice on the feet in the winter.

[PAToyota]

The best thing to do is just go with the recommendations of the manufacturer of the system you are using. I laid down reinforcing mesh and tied the tubing to that. Worked well and since it was 4"x4" it gave me an easy way to measure things for the spacing and all.

[86turbodsl]

Yeah, I designed my own, and it works good. Not cheap though. I used 1/2" oxygen barrier pex. Make your loops no more than 250' long If you use 1/2. I have one big zone for the whole shop, it's 8 loops of 250' pipe. Figure one linear foot for each square foot of shop. You should insulate the edges of the slab, and if you want it to be really cheap to run, put insulation down underneath. Use the 25psi foam. It's plenty strong enough to have concrete and machinery over it. When I figured it out, the weight of concrete and everything was under 1psi.
The floor temp should be 90 degrees or less, and that means you can't run a normal boiler without reducing the temp of the water to the floor. You could run a water heater turned down to 90, but that's not legal everywhere. I run an oil boiler with a variable speed injection system with outdoor reset temp variation. Most folks say it's overkill, but I'm an overkill kind of guy.
You can see pics of my install at my site:
http://86turbodsl.homelinux.net

Good luck!

[jdrocks]

know what type of pipe you're using-google up pex pipe to see all the fun they've been having.

[D60]

All I've ever seen mentioned here is the pex, but what about Wirsbo?

[indulf]

know what type of pipe you're using-google up pex pipe to see all the fun they've been having.

you arent getting PEX confused with polybutylene pipe are you?

big difference.

[TLCObsession]

PEX is a type of tubing, Wirsbo is abrand.

I do believe jdrocks is confused.

There are a few people on the board who know what they are doing, as well as a couple of us that have home brewed. I am about to convert a garage to living space and will likely use Warmboard despite the expense. But Scott is on the right track: fora residence, you need someone to properly design the system.

As for dialing down the temps, you can have a better system by using a mixing valve and blending the returnwater to get the desired temp.

Jim

[PAToyota]

I used the Wirsbo PEX and just took the binder that Wirsbo supplied and ran through the calculations and layout diagrams. Went together pretty easily. Have two zones, the tubing is looped about 12" apart, and feeds back to the manifold.

[jasonmt]

Are we talking garage/shop use or residential or both?

If you are spending any kind of $$$ for equipment with a wholesaler they will generally design the system and provide schematics for you.

My brother and myself are currently retrofitting in floor heat into his 25 year old acreage, we both have a good background dealing with this (it will be my fourth friend and family install) and we went with the wholesalers design.

With all of the design considerations involved it is really not a place for a "one size fits all solution".

Residential systems have noise considerations that a commercial or shop application generally will not. Something simple like a garage or shop is easily designed but if you are talking about a multiple control zoned system with a variety of floor coverings it becomes a complicated task. Budget plays a large part in in the selection of controls etc.

Your heat load, building specifications and local codes will be different from anybody else's here.

I prefer to use Wirsbo MultiCor which is a PEX-Aluminum-PEX product for most applications, especially for in concrete use.

[Ztec]

I dont know much about them but the hvac guy we use has some neat program on his laptop that does all the calculations and tells you how to lay it out based on room dimensions, window placement, which direction the exterior wall is facing, r-value and all that stuff.

[ScottFJ40]

Thanks for all the input. This is for my garage/shop that's yet to be built. i'll be pouring the pad soon though.

[jdrocks]

when i said PEX i was referring to cross-linked polyethylene and not to PB which is polybutylene. all i suggested was a review of the product-there seems to be varying opinions as to its use in closed loop radiant systems in particular.

[pmurf1]

I was reading the latest issue of HVACr news today in the shitter at work, and they now have an electric radiant strip that works the same way. Supposedly 250' draws about 12 amps FLA. It was just an ad, don't know if it really works well or not, but I can get the info if you need it.

[ScottFJ40]

I was reading the latest issue of HVACr news today in the shitter at work, and they now have an electric radiant strip that works the same way. Supposedly 250' draws about 12 amps FLA. It was just an ad, don't know if it really works well or not, but I can get the info if you need it.
That would be cool, the info if you can get it. I've never heard of that, not that that means anything.

[Ztec]

the guy we use to install radiant heat was at my jobsite today, I asked him what that program was called and its loopcad.

[ScottFJ40]

the guy we use to install radiant heat was at my jobsite today, I asked him what that program was called and its loopcad.
Sweet! I'd like to find a demo of that.

[PAToyota]

Ask and you shall receive... -- http://www.loopcad.com/

[pmurf1]

That would be cool, the info if you can get it. I've never heard of that, not that that means anything.

Scott, www.orbitmfg.com is the website.

[Tacodriver]

The electric heat strip works fine, but I have seen places where it has burnt out. Not real fun to fix the fault, it involved a concrete saw, jackhammer, rubber tire backhoe (me) and the customers (small apartment building) loosing their driveway for a couple of days.

[Lil Toe]

Here's a company that carries a lot the hose and parts to do it. I took bids for it when I built my place (TekSupply didn't carry this stuff then) and decided against it. Since I live in one end of my shop, I wish I would have at least done that part of it, that floor gets really cold in Dec/Jan.

www.teksupply.com

It's mentioned on the first page, couldn't get the link to work right.

[Toyota_Jim]

I used Wirsbo products. Several circuts in the shop, thinking I would use different areas more than others and adjust as needed but i just leave them all set the same...

All run off my outdoor wood boiler.

[hairy kanary]

Just something to consider...
I'm trying to rent a bigger shop for my lil' fab/welding business.
Found a smokin deal on one a few months ago, a near new shop on the outskirts of town.
We had the deal hammered out and the day before I was ready to move in I asked to meet the owner there to go over a few things.
Number one...where to mount my bender on the floor.
Also where to bolt down my lathe and my tippy big ol' drill press.
Nothing doing! He had radiant heat in the floor and wouldn't let me drill any holes in it.
He had no idea where the pipes where as he hadn't mapped a grid for them and hadn't tied them in very well before the pour so they may have shifted.
We kicked around several ideas but it was all going to cost ME far too much money so I killed the deal.

[86turbodsl]

To locate piping in the floor, two methods:

1. Pour alcohol on a cold slab. Turn the heat on to nuke. Where it dries up first, is the tubing.
2. Infrared heat gun.

[The Adam Blaster]

The piping should be at the bottom, or right under the cement, so drilling isn't a problem as long as you know how thick the cement is. Mine is between 6 and 7 inches. (Thicker on one side with a slight slope towards the big door.)
I will not likely drill anything large/heavy down, maybe some shelving, but i won't go below 2" into the slab, so no worries.

I have a whole long story about my radiant heat woes, all stemming from getting the wrong person(s) to install it. And the company that manufactured my boiler has shitty customer assistance and no field techs.
Short version of the story is that the guy that installed the boiler was a plumber, and when there was problems due to the electrical systems not working right, he had no idea how to fix the boiler. It was installed in January, still isn't working. I've had 2 different guys from the same company look at it this week, and a 3rd guy is coming by tomorrow and so far there is no idea how to get it working.
That's after asking a couple different friends (HVAC guy, and electrical engineer) in to look at it.

So, the lesson here is get a person or company that can troubleshoot everything, plumbing, electrical, heating/cooling etc. to install the boiler. I'm trying to get mine working before i go away for a couple weeks, and it does not look promising...