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Green Build AB
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Posts:14
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| 09/12/2009 8:30 AM |
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| This has all been great information. I think I am close to making a decision. Since the system is just that, I thought I would ask about the other components that are being proposed for the system. The retailer is suggesting Axiom manifolds and using a Super Stor ultra for the domestic hot water. There are 4 bathrooms in the home and a powder room, four people. It was suggested I use a 60 g tank. Any thoughts. Thanks |
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NRT.Rob
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Posts:733
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| 09/12/2009 2:23 PM |
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| do you plan to run 4 showers at once, 2 sets of 2 showers, or..? low flow or regular flow heads? |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Green Build AB
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Posts:14
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| 09/12/2009 7:35 PM |
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| QUITE OFTEN i WILL BE HAVING A SHOWER AS MY WIFE FILLS HER TUB. tHE CHILDREN ARE STILL YOUNG SO AS THEY GROW MAY RUNINTO ISSUES WITH THREE BATHING AT THE SAME TIME (NOT THAT LIKELY THOUGH). wE USUSLLY RUN OUR DISHWASHER AFTER GOING TO BED AND THE WASHING MACHINE OFTEN IS NOT GOING AT THE SAME TIME AS THE BATHING. aLTHOUGHT THIS IS A GREEN SITE, I WILL NOT LIKELY BE USING WATER SAVER HEADS. |
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NRT.Rob
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Posts:733
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| 09/13/2009 7:32 AM |
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for just a 5 GPM tub fill and 2.5 GPM showerhead running for 8 minutes simultaneous, you'd need 115kBTU+ boiler to use a 60 gallon tank. and your tub fill may be longer/faster than that.
I would suggest a 3 shower load OR a 7.5 GPM tub fill... not both... you look to a bigger tank. 80 gallons of storage gets you down to about 75kBTUs/output required.
this assumes 140 stored (tempering valve required), 110 at the fixture and 50 deg F water in the ground. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Green Build AB
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Posts:14
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| 09/13/2009 10:00 AM |
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I was looking at the Onix product. They say you do not need transfer plates. Can that be true?
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NRT.Rob
Registered Users
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Posts:733
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| 09/13/2009 10:07 AM |
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| if you are happy with lightweight plate style performance, it's true. it does not perform in the same ballpark as heavy plates. and I never recommend rubber pipe in any system. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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RadiantRob
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Posts:10
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| 09/14/2009 9:55 AM |
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Listen to Mr. Bean. I’ve watched his seminars and frequented his web site, he is very knowledgeable in all things “radiant heat”. Plus, he is a countrymen of yours.
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RadiantRob
Radiant Heat Designer
http://www.radiantdirect.com |
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Submission
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Posts:2
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| 10/13/2009 9:49 PM |
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| Green Build AB, what part of Alberta do you live in? I have found a couple very knowledgeable Radiant contractors in the Calgary/Okotoks area. One fella has been dealing with European equipment for years and uses 95% advanced building/green systems. He has been a wealth of knowledge and will be doing my radiant work. |
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Blueridge company
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Posts:211
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| 10/13/2009 10:26 PM |
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I can not see how onix pipe with out heat transfer plates can compare to a pex pipe with heat transfer plates thin or thick. period.
our plates tightly wrap the pipe and have a surface area of 5 inches of contact plate to floor. The onix pipe though high quality and very flexible is not making contact on the floor in areas other than where it is attached (tacked). so it in essence will rely on heat radiation in the air space as any pipe would equally. I am not sure I understand where the performance is coming from, the rubber?
am I missing something?
Dan |
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Dan
BlueRidgeCompany.com |
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NRT.Rob
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Posts:733
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| 10/14/2009 12:25 PM |
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it's similiar to light plates because light plates aren't that great in a joist in the first place, and the onyx deforms more when it is stapled, so you get more direct conduction to the subfloor in that case than you do with pex.
but you don't get heavy plate level performance . |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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jbaron
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Posts:43
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| 10/14/2009 1:08 PM |
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What are some examples of "light plates" and "heavy plates"?
Thanks,
Jeff |
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NRT.Rob
Registered Users
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Posts:733
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| 10/14/2009 2:01 PM |
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Thermofin, Joist trak and a couple others are heavy gauge plates. they are extruded and fairly rigid. You couldn't cut them with tin snips.
lightweights, you could. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Dana1
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Posts:702
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| 10/14/2009 2:05 PM |
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Posted By jbaron on 10/14/2009 1:08 PM
What are some examples of "light plates" and "heavy plates"?
Thanks,
Jeff
Thin sheet-metal "light" plates:
vs. extruded "heavy" plates:
The heavy plates have a better contact/grip between aluminum & PEX, increasing the thermal transfer efficiency from the pipe to the plate. (They also protect the PEX from nail damage through the floor.) The sheet-metal plates trap the PEX between the plate & sub-floor, whereas the extruded plates have the full thickness of the aluminum between PEX & sub-floor.
Heat transfer characteristics between plate & floor are similar between the two- it's the greater effectiveness of getting the heat out of the PEX and into the aluminum that is key to the difference.
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jbaron
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Posts:43
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| 10/14/2009 3:07 PM |
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Thanks. Can either of you hazard a guess as to the difference in heat transfer between, say, a 130 degree water and an 80 degree floor? Or, to where I'm really trying to go, what the difference in reset temperature would be in a typical installation? I know, lots of variables, but if the heat transfer between the extruded plates can save me 3 degrees of reset, that's something.
If not, thanks anyway,
Jeff |
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NRT.Rob
Registered Users
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Posts:733
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| 10/14/2009 3:11 PM |
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| in a typical, say, joist application, you'll easily drop 20 degrees of water temp over lightweights, using the heavy plates, to achieve the same output: here, "typical" assumes about 20 BTUs/sq ft and a wood floor. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Blueridge company
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Posts:211
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| 10/14/2009 8:47 PM |
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Ok,
I'll bite what supports this statement?
"it's similiar to light plates because light plates aren't that great in a joist in the first place, and the onyx deforms more when it is stapled, so you get more direct conduction to the subfloor in that case than you do with pex."
What is the staple pattern? Are you setting your staples enough to deform your pipe to be held tightly against the floot for the entire 300 foot run? is this the recomended design by factory?
That pipe is pretty bendy, are you taking every 2 inches?
Where is the math,
I do not buy that this squashed onix pipe system approach will out preform our RHT heat transfer plates with a 1/2 pex pipe captured securely with 5 or 12 inches of surface sub floor contact depending on the duel or single pipe plate. This sounds like more bias against the .020 guage stamped plates.
wheres the math?
Dan
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Dan
BlueRidgeCompany.com |
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NRT.Rob
Registered Users
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Posts:733
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| 10/15/2009 8:29 AM |
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watts has plenty of performance testing on this, though they do include benefits from a reflective layer of insulation below as well which I would typically discount. if memory serves, that helped them exceed light plate performance, but they are in the same ballpark in any case. which is to say: it's a high temp application for all but very low heat load situations, by my metric (over 120 degree F supply temps typical).
I understand you really like the plates you sell, I like lightweights too in the right application, but let's not be obstinate. there is an entire industry out there using heavy gauge plates to very good effect. your disbelief does not change the facts. so the "bias" against the light gauge plates is not so much bias as "reality". You keep talking about subfloor contact but you do not address the carrying capacity in the aluminum in the first place, which is the bottleneck fixed with heavy gauge plates. I could make your plate 10 feet wide, would that be the same thing as having 10 one foot wide plates?
as for Onyx, it does deform quite a bit when stapled. do your homework if you're interested and you'll see. it is how the factory recommends installing it. that does significantly increase direct conduction to the subfloor compared to any pex, which should NEVER be installed with staples like that or you can chew through the pipe over time... less of an issue with PAP perhaps, but PEX can die an ugly death on high temp staple ups.
If you're interested in the math, feel free to produce some. Frankly my calculus is about 10 years rusty at this point so I don't have the math. |
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-=Northeast Radiant Technology=-
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Blueridge company
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Posts:211
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| 10/15/2009 11:32 AM |
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So,
If I understand correctly lets lay out the systems;
watts can achieve the the same heat capacity in a staple up configuration as pex pipe with .019 heat transfer plates however they factor in the use of a insulation foil product. (though they do include benefits from a reflective layer of insulation below as well which I would typically discount). why would this be discounted, it is essential in there calculations to closing the cavity.
This speaks volumes to there logic, why not use a plane pex staple up on a tight pattern like 6 inches using proper staples to assure close contact to sub floor and the same reflective layer of insulation below, I suspect you would have the same result, there onix pipe has no magic advantage over heat transfer of pex pipe. Its glorified bendy radiator hose.
Watts pipe about $1.90 per foot plus the foil that is required to close the cavity. (shopping on line, delivered)
NSF pex pipe 1/2 pex pipe @ .28 per foot / heat transfer plates @ .74 foot $1.02 foot (shopping on line, delivered)
Now add the foil to close the cavity,
I do not see any advantage to ONIX, in fact it looks 2x the cost.
It is bendy, and easier to work with, but if your pulling 5,000 feet of pipe there is a substantial difference in cost.
Rob, Your argument is not holding up.
Dan
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Dan
BlueRidgeCompany.com |
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NRT.Rob
Registered Users
Advanced Member
Posts:733
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| 10/15/2009 11:51 AM |
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Dan, you get much more surface area on the subfloor with onix than you get with pex. that's a plain fact. I agree that they inflate their situation with the reflective foil, I do not advise the use of foil in joists, and I hate onix and never use it. They also don't say "as good as light plates', they say it's "as good as plates", which is a lie if you are looking at heavy plates.
but the fact is, it'll run output about as well as your plates in a joist bay. which is to say, it's not very good. I say this as a fellow who has acres of light plate joist systems out there I helped design before discovering heavy gauge plates.
Then you turn around and compare it to non-barrier pipe? Way to load the argument in your favor. lesson number one: when going head to head against an opponent you think you have beat, give them every advantage. Otherwise you look like you're scared of a fair fight. onix is a barrier product. use barrier pipe in your comparison. you'll still be cheaper, so why inflate the issue?
the big selling point of onix is that you don't have to grind any nails in retrofits, you just weave around them. that's big, and it's why the stuff is popular at all. grinding off 1000 square feet of protruding nail heads sucks. I can see why installers want it to be good.
But regardless: I never said onix was a good choice. I think the stuff is crap. I only said that its output is equivalent to light plates, which I also think are a poor choice in a joist bay. I haven't tested onix, but knowing what I do know of heat transfer, I find their claim very believable. You don't need much improvement to get to light plate performance, and onix will give you "not much improvement". |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Blueridge company
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Posts:211
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| 10/15/2009 3:24 PM |
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Ok,
I appreciate the honesty about your use of Onix, for some reason that confounded me you sounded like you were promoting the new squished pipe method, hydronic industry changes fast!
Still not sure how you are getting more surface area of pipe in the sub floor. 300 feet point of contact is the same on ether pipe.
On my defense our RHT PEX C is SDR9 NSF potable approved, Barrier, American made (by Americans) and $.279 per foot ($279.00 1,000 feet) delivered.
Our RHT Pex B is SDR9 NSF Barrier (non Potable) made in China (by Chinese people) .269 ($269.00 1,000 feet).
Our RHT Pex B is SDR9 NSF Non Barrier ( Potable) made in China (by Chinese people) .24 ($240.00 1,000 feet).
NSF is the rating agency that inspects the manufacturing fracturing facility's around the world much like CSA or UL to be sure they are adhering to there strict guidelines.
Dan |
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Dan
BlueRidgeCompany.com |
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