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RothTechDept
Registered Users
Posts:1
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| 03/17/2006 1:08 PM |
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I have found that there are many misconceptions of what works and how to design a radiant system.
I recommend emission plates on all joist systems, no exceptions.
A room by room heatloss is mandatory for any design.
The heatloss for forced air, is different from radiant floor.
Be careful. You should always deal with a trained heating contractor who has the support of wholesaler and a recognized radiant manufacture.
Stephen E. Kelly
Technical Manager
North America
Roth Industries, Inc.
77 Circuit Drive
N. Kingstown, RI 02852
401-267-9044
401-267-9048 fax
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NRT.Rob
Registered Users
Posts:360
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| 03/17/2006 2:05 PM |
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there are always exceptions, stephen ;)
-=Northeast Radiant Technology, LLC=-
www.NRTradiant.com |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Unregistered
Registered Users
Posts:2321
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| 04/01/2006 3:32 PM |
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I understand doing a room to room heat loss, however what changes can you actually do? Instead of 12 inch on center go with a 8 inch on center? Thats basically it right? Whats the minimum bending that a 1/2" pex can take? IS 6" on center too much and may risk kinking the tube?
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NRT.Rob
Registered Users
Posts:360
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| 04/01/2006 4:33 PM |
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Load calcs tell you:
Tubing spacing in some applications.
Plate types, if any, that are needed.
what other applications may make sense, if several are possibilities.
whether or not radiant floor even makes sense for you.
whether or not you need supplemental heat.
if you need supplemental heat, what kinds make sense.
Whether changing a finish floor type could prevent supplemental heating needs.
your required flow rates.
your required water temperatures
feed pipe sizing.
heat source type selection
heat source sizing
pump sizing.
zoning requirements
whether or not outdoor reset, floor sensing, or other features would make a big difference for you, or not.
Basically, it tells you everything you need to know about a radiant system (if, of course, you know what to do with the numbers)
-=Northeast Radiant Technology, LLC=-
www.NRTradiant.com |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Unregistered
Registered Users
Posts:2321
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| 04/01/2006 6:27 PM |
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What I am saying is if a home is very well insulated and the loss load is low and wood floors or tile will be used that all these other instances will not come into play, correct?
Can someone tell me if a 6" on center is do able for a brand of 1/2" pex like Mr Pex brand?
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NRT.Rob
Registered Users
Posts:360
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| 04/03/2006 12:22 PM |
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Absolutely not. What kind of heat source are you using.. and WHY? How about controls? Plates? How do you know the "load is low"? How low is it?
I'm not saying it's impossible to get a working system without doing the loads. But you're guessing your way through. It may even "probably" work. but it might have been much better in a different configuration.
In very low load circumstances, I question the reasoning of going with floor at all. It won't be warm, so why spend the money? go with radiators or ceilings instead of floor and potentially save some big bucks. Or if floor is what is desired, you may very well need floor sensing to keep the floor from getting cold between infrequent calls for heat.
Stuff like that applies pretty much no matter what. There are always tradeoffs and considerations.
-=Northeast Radiant Technology, LLC=-
www.NRTradiant.com |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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onlyinamerica
Registered Users
Posts:16
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| 04/03/2006 4:10 PM |
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jmbeam,
Are you doing staple up? If so, then you're limited by your joist spacing. If you consider a 16" spaced floor joist then you're looking at 8" spacing, roughly. I have 1/2" Mr pex in my basement, porch and garage spaced at 12". The basement is a walk out with 1/2" styrofoam insulation and the garage has 2" perimeter and 1/2" interior insulation. It works great. The basement, which is unfinished and uninsulated is very toasty. It's not the "standard" 2" for the basement but it works great. I'm extremely satisfied. The garage works great as well. The porch, which I won't be turning on much may be too far spaced after looking at it now but that won't be something I'll be turning on often. I'll see how it works for melting snow/ice sometime next winter.
If you're shooting for 6" bend radius you're cutting it too close. I think 8" radius is what you can go for. I have an area with TJI's spaced at 12" and had to "needle and thread" the pex through those areas rather than "flip bend" pull through if you know what I mean. 16" spacings are no problem.
onlyinamerica |
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NRT.Rob
Registered Users
Posts:360
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| 04/03/2006 5:52 PM |
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to get a 6" spacing, you generally make an 8" bend and make it look like a "spoon head".. so the straights are at 6", and it bows out to make the larger bend.
Mr. pex can technically make a 6" bend clean, but you need to do it carefully or it will kink. Of course, if it does you can heat it up and let it reform and try again. but the spoon head method is a lot easier.
-=Northeast Radiant Technology, LLC=-
www.NRTradiant.com |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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