hey guys, I want to thank you guy for a great site. I have been browsing it for quite awhile now. I am hoping you guys can help me out here. I removed my old, in-effecient heating system (including the in-wall radiators) and put down radiant tubing down on the sub-floor. I want to be absolutly positive that I did it correctly. Each room has less then 300 ft of 1/2 inch oxy pex. The main feed line start off at the external walls and the second row is 6 inchs apart. After that each line is 10 inchs. There will be a 1.5 inch mud job over this, then tile OR floating wood floor. Each room consists of ONE loop. Does this look and sound correct?? I am single one-income guy, I cant afford to hire people to do this for me. I am def handy (solder,electrical work,carpentry,etc) I jsut need some guidance, I hear to many diff opinions.

thanks!!

OK> I cant attach pics????

 

Try photobucket and post the link over here.
Image hosting, free photo sharing & video sharing at Photobucket
Bud

 

Good idea Bud, thanks!!


heating project pictures by Gnfanatic - Photobucket

 

Umm, well...

1) did you size the tubing and the tube spacing based on a design water temperature and floor covering that will provide adequate heat output to meet the heat loss? In other words, how did you arrive at that tube spacing, and what will be the required water temperature to meet the design heat loss? (Hint: you don't want the surface of the floor warmer than about 85F. And a tile floor will most likely require a different water temperature from a floating wood floor.)

2) what is the design flow rate and temperature drop?

3) how long is the "ONE" loop? Typically, radiant loops are sized to be about 200 ft long, max. More than that, and it takes a much bigger circulator to try and cram the water needed through a very long, thin straw. Bigger circulators cost more to purchase, more to operate, make more noise, etc. The longer loops have a greater temperature drop, etc.

4) what kind of boiler is being used, and if necessary, how is boiler protection from low temperatures being provided?


Radiant is not hard to get right, but it's a real pain to get wrong. Let's see the homework you should have done to design this system, and that will determine where we go from here.

 

1) did you size the tubing and the tube spacing based on a design water temperature and floor covering that will provide adequate heat output to meet the heat loss? In other words, how did you arrive at that tube spacing, and what will be the required water temperature to meet the design heat loss? (Hint: you don't want the surface of the floor warmer than about 85F.) No I did not . I based it off what I have been told by people. I also went off how the people did my parents house. I was told that 1/2 oxygen barier pex is fine for residential.

2) what is the design flow rate and temperature drop?

I do not have one nor was I told it was needed

3) how long is the "ONE" loop? Typically, radiant loops are sized to be about 200 ft long, max. More than that, and it takes a much bigger circulator to try and cram the water needed through a very long, thin straw. Bigger circulators cost more to purchase, more to operate, make more noise, etc. The longer loops have a greater temperature drop, etc.

Each room is one loop. the 2 bedrooms are roughly 150 ft long each. the livingroom is roughly 220 ft, i can measure for exact numbers. I was told 300 ft max for 1/2 inch.
4) what kind of boiler is being used, and if necessary, how is boiler protection from low temperatures being provided?
I am going to be buying a he triangle tube boiler. I have spoken to the engineers there and discussed about the my application. They told since I am doing all radiant to use certain type of pumps for each zone.

See , this is what I did not know. I sent these pics to radiantec.com so they can put together a system for me. They said i did the tubing right based on the what I showed them with the blue prints. I am just worried that it can be designed better. becuase once the mud gets put down thats it!


thanks! hopefully I dont look like an ass !

 

Practicing professionals generally think very little of radiantec. At least that's what I've gleaned over the years, and it's putting it rather generously.

I strongly suggest that you back up a few steps before it's too late. Start by getting a copy of John Siegenthaler's book "Modern Hydronic Heating" from your local library or ordering online.

There are also two good publications by the Radiant Panel Association, titled Radiant I and Radiant II. Go here:

Radiant Panel Association

and rummage around. Most of what you need to know to get this right is contained in these three sources.

On the bright side, the Triangle Tube boiler is a good choice. Get the right size.

Do not be in a hurry. Getting it right from the point you're at might take a week or two. Getting it wrong can be very expensive and will last the life of the house.

 

And this is why I didnt not go ahead and do the mud job. He approved of it and designed my system without out knowing the heat loss of the house. I also asked him does he need any info about the boiler, he said no! I am like wtf/ this does not make sense!!! When i asked him about the pics he says it looked good to him just make sure everything is evenly spaced!! I am going to start reading up! I put alot of energy in this house and sure want to do it right. i just cant afford the $15-$20K estimates I have received and there still is NO guarantee of a proper design!

 

xi, that book is $175. If it will answer all my questions I will be more then happy to buy it. Is it worth the cost?? I believe software comes with it?

 

Shop around for the book... you should be able to find it 25-30 cheaper than that. Or, check your local library! Even if someone scoffed the CD-rom, the book is a gold mine.

 

Try the library. The RPA pubs also cost.

$175 is what, 1-2% of what your project will cost? That's peanuts considering the alternative.

 

You capped those lines and put air pressure on them while you work this out (and everyone's walking all over them..) I hope ? Put a gauge in the line and remove the source air. That way if you have a small leak (or someone pinches a small leak for you), you can discover it before its too late.

We went with loop per room also.. and the 6" spacing at outside walls then 12" after that. Each room is controlled by a tstat which opens a valve. One circ pump for the loops in a shared header pipe via a mixer, and one circ pump for the boiler loop (although Trooper pointed out that its non-conventional )

You came to the right forum for your project, these guys are an absolute gold mine.

 

xi, I agree about the cost of the book, I ordered it. Dave, I am going to pressurize the tubes when the mud goes on.funny, my tube layout is almost is exactly like yours except for teh 12 inch spacing, mine is 10. How did yours come out?

 

The 6/12" layout seems to work fine here. The lines are tied to mesh that we tried to keep about in the middle of a 5" slab. On the slab for some rooms is ceramic and/or porcelain tile.. some other rooms have laminate flooring (with that floating foam under it).
Are you going to have 1.5" of mud over top of the pipes.. or the pipes are in the middle of 1.5" of mud total ? I think you need a decent amount of material above the lines to allow the heat to spread out some (so you dont get cool/warm stripes).. that book probably deals with that.

To be honest, other than one area where all the pipes come out from the boiler room and turn their routes, my floors dont feel "warm" to walk on. They're not cold (certainly not as cold as tile on a concrete slab would be.. yikes), I guess theyre just "room temperature". I think you'd have to be shedding alot of heat (ie, very lossy house) in order to have enough btu bleeding from the floor to make it feel "warm" like the sales brochures seem to indicate.

Dont forget some of the other tricks for hydronic that ppl use.. like a loop into the bathroom for a custom towel dryer/warmer rack ! (or maybe a boot/mitt drying rack ?)

 

Dave, is your radiant floor the only source of heat in your house? the tubes will have 1 inch of mud on top of them if you think about it. My parent floor is warm. I dont understand how your floors arent warm but still keep your house warm?