Onyx vs plates

Bruce M_2

Onix for the most part is made of EPDM which is the material used today for automotive and truck cooling system hoses. A look at the Watts waranty is in order. It states: "Note: Watts Radiant does not warrantee its piping unless Watts Radiant branches and clamps are used in the installation." The warranty is not valid if the water temperature normally exceeds 180 degrees. Here is a link to a very interesting article by the Gates company concerning problems with EPDM in automotive cooling system. This may explain the "sludge" that is seen by some when using Onix.

Wayco Wayne_2

I know, I know

Being a plates & pex guy for so many years, it feels like a scene from star wars to consider the onyx tubing. (Go to the Dark Tubes Luke Skywalker.) But... It's been around a long time. They have the engineering data to size & design with. If it didnt work they'd be gone by now, right? Just Looking for a hedge in price and labor costs. What is your experience???? WW

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Steve Garson_2

I have my master bedroom and tiled bathroom heated with Onix. I've been happy with it. For the energy purists, it does require a higher water temp than PEX, but I have no complaints. My 3/4-inch oak hardwood floors over 3/4-inch plywood with cathedral ceiling and Cathedal North wall need 125* water temp, with 140* when it is around 20. When the outside temp is at 10*, the system needs the auxiliary baseboard and 150* water temp, which is as high as I go. It's completely silent.

Very easy to work with.

But I am a sample of one. I have no comparison.

Steve

Ruthe Jubinville_2

Just an FYI

Jerry used onyx for staple up and pex in concrete. very easy to install labor wise. He never had a proble with it not doing the job. used 150 degree water or less with foil baacked insulation underneath. I have it or polybutylene in the rooms that I have radiant in. kitchen and bath done in radiant. best heat in the house. Ruthe

Leo_15

The Company I work for

The company I work for uses pex to hook to baseboard since copper went crazy in price. All radiant is done in onyx due to ease of installation. No plates, and I believe they run two runs per joist bay but I am not sure I can check. No customer has complained abount insufficient heat. We have a few accounts we inherited that don't complain either. One draw back is some of the earlier onyx seems to not have a good O2 barrier. We get a lot of black build up in the system water and it corks up spirovents. Personally I have only installed with copper so pex or onyx is all foreign to me. They spare the "older guy" from doing heavy work.

Leo

Unknown

it's staple up, minus a few degrees. if staple up is a good solution for the job you are looking at, so be it, but I don't think anyone is doing anyone any favors designing 150 degree radiant systems when you could at least add a little baseboard and get it down to a much, much lower operating temperature.

personally I don't trust rubber long term and the 'mystery sludge' I keep hearing about only convinces me further.

I'd do a suspended tube instead, every day of the week, with PEX or PAP. it would be cheaper to boot.

it is not equivalent to heavy plate systems.

Wayco Wayne_2

Rob

Thanks for Chiming in. What is this mystery sludge you're talking about? I did the engineering for plates and onyx. Suspoended tube needed 156, Plates needed about 115 according to Uponor software. Onyx needed 126 according to Watts software. 126 still condenses my boiler. WW

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Unknown

I think the watts software is very optimistic and includes reflective insulation benefit you could add or discount equally with regular staple up/suspended tube. Suspended tube and staple up perform very similarly; I don't think there is much magic hoodoo here that makes a marginal contact area increase that much better. I'd give it ten degrees over regular staple up and call that a reasonable ballpark. But, that is speculation, so don't let me sound like I've done the testing or anything, just read the marketing materials that require the reflective insulation to hit the water temp claims they put forth.

Personally, I don't ever rely on upward reflective foil for long term performance. Of course, I haven't heard about a slew of failures after a few years of installation in such systems either due to dirty foil. I just choose not to risk it.

I keep hearing about black sludge in these systems; another poster in this thread mentioned it again. I don't have an explanation except I don't think it can be related to the o2 barrier, as systems without o2 barriers don't usually get black sludge, they choke on rust. I suspect the rubber breaks down over time, personally, and I don't see how anyone could think it wouldn't.

I am a nervous nelly about a lot of things though, so I wouldn't judge anyone else for not sharing my misgivings. just talking through my own thought process on the matter.

Watts is coming out with a graphite matt next month that should allow similar installation benefits and better performance. I'm really looking forward to seeing what the pricing is on that product!!!

Glenn E Sossin_2

Marginal in staple up

Simply put, air is not a good medium for conducting heat energy. The plates are always better for this purpose, regardless of type, which is why the temps are always lower.

Obviously there are situations where the staple up will work if the room heat loss is relatively low. Consider if a customer, at some later point, decides to put down carpeting - it is likely the onyx will not release sufficient heat energy into the joist bay to heat the carpeted floor. Even if it could, it would likely require 170F - 180F type supply temps.

The plates probably could heat the retro-fitted carpet floor simply by raising the water temp 20-30F. That extra temperature head room may not be available for a staple up installation.

Another negative of the onyx would be the higher temps necessary for successful operation - especially if there is a condensing boiler involved. The temps required may be so high, the boiler wouldn't be able to condense.

We usually use the extruded plates where the pex snaps in from underneath. While slightly more expensive than the thinner alum transfer plates, the extruded plates are a big labor saver as well.

What would be interesting to see is a performance test that compared onyx in a mud job to conventional pex. I suspect there would be minimal difference if any between the two - which then lends itself to the question, why pay more for the onyx tube in a mud job if there is no performance benefit?


My $.02
Glenn

Wayco Wayne_2

I don't think

anyone in their right mind would pay extra for onyx to put it in a slab. At least I know I wouldn't. I think the Onyx is stapled tight to make direct contact to the sub floor since the expansion rate of the rubber is far less than the plastic tubing meaning less noise from the Onyx. Since the Onyx can make contact without the noise it can make direct heat transfer to the sub floor. (in theory) Of course the extruded plates are 4 inches of contact compared to 1. But they have been in business a long time. If their engineering charts were faulty it would have caught up to them by now. I have no experience to draw from, but I have one more room in my house that needs radiant floor and I just bought a roll of onyx to test it out. Of course I won't have any findings until this Winter. I am also awaiting the graphtek blanket picked up by Watts. I'd like to test that in my house too. Anyone that has experience with Onyx please share or at least E-0mail me. WW

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Ruthe Jubinville_2

another FYI

my staple up with foil reflective has been in for 18 years. Heats equally well until vinyl floor tiles and carpeted areas. No Plates. and mine has to work overtime to help heat the rest of the downstairs rooms since they do not always stay up to temp settings and my kitchen keeps up or overrides just slightly. All in all it is the best heat in my house. Ruthe

Unknown

I'm considering onyx to for supplemental floor heat in a panel radiator job. The basement joist bay is a jumble of wires and pipes and I think working with pex could be very difficult in this situation. Plus I think the onyx operating temps will be very compatible with what I will need for the radiators, thus keeping things simple.

From an ease of handling perspective kink proof rubber tubing and pex are very different materials.

[Deleted User]

Gunk...

No better way to decribe it other than calling it gunk.

The Heatmeister has substantial experience with it, to no avail. Has even tried the best/strongest hydronic cleaning solutions available, and still, GUNK.

To me, it indicates SOMETHING is coming out of the hose. Plastisizers? Polymers? I do not know, but I do know this. I have had just ONE vehicle that I have NOT had to replace the hoses on. And for the record, that one vehicle didn't use water as a cooling medium. (VW Bug)

With that said, I would never subject myself or my customers with the possibility of having to replace the hoses in their comfort system.

Now I know they have a STRONG following, and some of their reps are my best friends, but after having witnessed the debacle created by Entran II, you won't catch me with rubber hose anywhere near my systems. (I also know that Onyx is not considered "rubber", but if it walks like a duck, talks like a duck and smells like a duck...)

ME

Unknown

you think it would?

I think mfgs can wiggle out of anything. If your onyx comes up short, are you going to sue watts, or turn up your water temp and assume that the load is a little higher than you expected, or that throw rug must be throwing you off a bit, or.. or... or...?

Wayco Wayne_2

Thanks Mark

Why don't you stop **** footing around and say what you really mean. Ack! Where does this gunk manifest itself? Does it cause clogs in strainers. Stop zone valves from working? You're also inferring that the tube will some day wear out. Does Heatway have any computer projections on lifespan of the tubing like the pex guys do? (100+ yrs computer projections) BTW My first car was a 63 VW bug. got 30 MPG and was easy to work on. I replaced the engine with junkyard engines 6 times. I loved that car. It got a little rusty though. I knew I was getting near the end when I ran through a puddle and got splashed in the face through the heat vent. WW

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hot_rod

the current version

is quite a bit stiffer then the earlier Entrans. No doubt the aluminum layer added for O2 protection has contribuited to that. Use a lot of (heat transfer) staples, even closer then the recommended spacing.

My painted demo showed even tightening the staples, with a hammer didn't give you 100% contact along the tube even at 6" staples. Over tightening seems to alter the fluid channel dimension, inside.

Floor temperature spread is not quite as even as with plates, as seen in the FEA and infrared pics.

Staple up can and does work, just be away of the output and temperature profile difference.

The gunk is another concern. Some systems fluid's stay as crystal clear as the day they were installed, others develop chronic sludge issues. Is it the tube, water quality, bacteria? Regardless I've not seen it in barrier PE tube systems even cast iron boilered ones.

hr

Unknown

Remember that automotive hoses operate in a dynamic environment, that includes vibration,road salt, oil, much wider temperature extremes,and far more cycling of those extremes. I'v seen some worn out cars with original hoses looking fine.


I think it's a good bet that well pex will last longer than "rubber". But seems to me that a "rubber hose" protected from those kind of extremes should have an reasonable service life. Is this gunk being found in the newer style hose?

Wayco Wayne_2

Those pictures

say a lot. Thanks for posting them. The pictures show the un-rivaled power and capacity of the plates. They also show why plates have more pronounced striping. I switched my system in my kitchen from suspended tube to plates last Fall. The reason?? More power!!! That's what I want MORE POWER!!!!!!!HAHAHAHAHAH! But...I noticed the striping, and didn't like it. Before the warmth had been more even. I liked it better before even though it was not as powerful. And there's the rub. It's safer to install more power/capacity as per extruded plates, but not perhaps without compromises in comfort to the feet. That's why I am VERY curious about the new graphtex product. Will it reduce the striping? Will it work better with pex or onyx? Will John from Graphtex use my house as a test site and give me free product for mentioning them on the Wall multiple times? I guess only time will tell. BTW as I am writing this I am installing some Onyx on the bottom of my Dining room floor. The flexibility is nice. Using the crown stapler is very fast even though I am stapling every 6 inches. The only negative so far is the roll was too small in the middle to fit on my uncoiler. I am also removing the insulation from under the rest of the radiant floors and am going to install thermo pan reflecting board to make an air space to see if I can even out the temperature of the striping where the plates are. Why not, couldn't hurt. Well now I stalling. Back to work. WW

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Darin Cook_5

Take it from someone with MILES of Onix installed

It works and works well. Do your math. Obey your numbers. The Radiant Works software has NEVER failed me. If it says to use supplemental heat then use it. It is WAY, WAY easier and faster to install than extruded aluminum plates with pex. What does this mean to you as a installer/business owner? The ability to sell and install more profitable radiant jobs and feel extremely confident that the homeowners will be happy and comfortable.

The highest Onix design temperature job here in my neck of the woods that I have done is 135'. I believe that is below condensing, and that is on design day. So every other day during the winter it must be even lower on the condensing scale. Some of the people here who are being critical with the product are design only folks with no practical field experience.

As far as the Entran II issue - guess what - what did it turn out to be in the end? The product was not made to Heatways standard.

I think that if Onix can stand up to being used as the piping for solar panels, it can stand the test of a low temp radiant floor.

You want the lowest operating temperature for a radiant staple-up? Use extruded aluminum plates with pex. Then go to a customer and explain that you realize that plates will run only 10' or 20' cooler than Onix. Explain that they will not to be able to "feel" any difference and also explain that you are sorry it is thousands more to install the plates. BUT tell them you are a Real Radiant Purist and this the absolute best way to install a radiant heating system. Hey if they cannot afford the plated system they should not have a radiant heating system anyways right? Wayne, I believe that you will not have a problem with your system in an environment even more milder than mine.






Darin

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Unknown

miles?

you can do miles in one job Darin

tell the customer five years later why you are replacing half the components in the heating system and having to do a total system clean to fix the gunk issue. Maybe you're a lucky one, but we've seen it and choose to never gamble. At the time I assumed there must have been some kind of leak in the system. Now I hear about it from others too. no way.

and if you think a 20 degree water temperature drop is inconsequential, I'd say you're not running numbers on the system options. Staple up has a place, and that place is with an informed owner making an informed decision about their short term and long term options.

If they really want to save money, talk ceiling before you talk staple up. similar price range, far better results in most cases.

If not, go staple up. I still wouldn't use this pipe, but you have lots of people who agree with you. For me, when I see this gunk issue with PEX, ever, maybe I'll change my mind.

Darin Cook_5

It is a free country to be sure!

So we can all pick what we want to use. I too, believe that my customers should make informed choices. There are systems that I have installed that this year will have been operating for a decade. I know of no problems. Water quality issues that some have described, I have not found that issue. So I cannot presume to know what is going on in those cases. Should they be pursued to find the answer - Absolutely.

My point with the (DESIGN DAY) system operating temps 130' vs 115' or whatever is that I challenge you to prove to anyone how much more efficient that system (pex/plates, which is still considered staple-up by the way) is over Onix. I want to know the return on investment timeline between the two. If you are maintaining floor temps at 80', please explain to me who can tell the difference?

The area of Upstate NY that I live in has a tremedous amount of old gravity hot water systems. These are threaded steel pipe systems (great oxygen barrier). When you drain these systems they are filled with this nasty black sludge fluid. What is up with that? Oh my goodness - we better rip all of these things out right now.

Now what about the delamination issues of the pex O2 barrier. What about all of the chafing that must occur with that expanding pex going back and forth as it grows magically in length, in the extruded plates?

I have seen this debate played many times before. In my opinion the fight should not be between any of us or product preferences. The fight should be to make everyone know just how great radiant heat is! It is the MOST COMFORTABLE hands down. You want the MOST EFFICIENT system with a radiant benefit, go with steel panel radiators and a mod-con!

Let me say this in conclusion with how I started my other post. Run your numbers, Do your homework, How many btu's per square foot do you need? Make your decision based upon these facts.

Wayne - Good Luck, My Friend!!!!!









Darin

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BC_13

Good points and I generally agree that a 20deg drop in water temp won't make a huge efficiency difference. The one case I want to point out is for hydronic heat pumps, where a difference between 100F and 120F can mean a 30% efficiency delta. The difference between 120F and 130F is even more critical as most heat pumps aren't capable of supplying more than 115-120.

hot_rod

Striping goes away

to a certain degree when floor coverings are added. The pic show plates and Onix under bare Advantech subfloor material. Add wood, tile, whatever, as seen in the back half of the picture, and the striping lessens.

Also note the effect carpet has on output in that picture. The back half of the sheet has carper, thick berber, but no pad below.

With less conductive transfer the carpet and pad will really cut into the output.

If moving the energy to the floor, and through the coverings as efficiently as possible, there is no question conductive transfer, via aluminum, or graphite will be the best.

The aluminum layer on the Warmboard, even with 12" on center tube space is obvious in this picture.

Also notice where I pulled the transfer plates away from the subfloor to make the crimp connection.

hr

Supply House Rick

I have sold Darin miles of Onix and many others

Back in the wholesale days, I sold miles upon miles of onix and can't remember one call-back or system failure due to "gunk" in lines. Maybe we were just lucky in the northeast and I am not saying it can't happen. I certainly respect Mark Eatherton's opinion, just have to say haven't seen a problem since the the old Entran II days. Darin's work and opinion is beyond reproach on this site. He has posted some of the best looking installs most have ever seen, it may just be working for him...

***Here's a shot of some Wall illuminaries at Darin's wedding to the lovely Anne

Unknown

here in maine, we have seen those issues. I'm not saying it's common, I've only personally seen it once, but the issue exists for onix in the northeast.

hot_rod

Will the Onix run solar temperatures?

Knowing an evac tube system can stagnate at over 350F under no circulation conditions.

Earlier version of that product had 325F intermitent temperature numbers.

hr

Andrew Hagen_3

Published Output

The output numbers published by some manufacturers are outright deception. The problem is, if they don't make it look a little better than the competition, then how do they sell it? "It's not as good as X but it's cheaper" That's a tough sales pitch.

Any analysis I have done of FEA output for extruded plates showed that the true output for plates was the same or a little less than what Watts publishes for Onix. I know that is not true from a similar FEA analysis of bare pex and common sense.

I would just take the manufacturers' published numbers with a grain of salt and go by my own experience instead. Fact is, plates are a tough sell. Aluminum is expensive, and it requires quite a bit more labor to install it. We want to believe that Onix will work fine in nearly all situations, because if it doesn't, it could very easily make the difference in getting a job when competing against the other guy who doesn't bother to think about the heat load. Onix obviously can and does work, but it would be nice to be able to rely on the performance advertised in the literature.

[Deleted User]

Gunk manifestation...

Yes, it shows up in pumps and locks them up, as well as certain zone valves. It is heavy, so it accumulates in the lower regions of systems, like the basement. Although I have not seen it completely block the tube flow off, I did witness that happen with the E2 products.

ME

Rod Kotiga

Yeah, I noticed that as well. Onyx for supply & return runs on solar ? Hmmmmm

Rod

Leo G_102

Wayne

just to let you know, I have installed Onyx with a variation of the "cheap" aluminum plates. Found some that fit nicely over the 3/8's. Hardwood throughout, so had the general double up the ply sub floor so as not to worry about the nails. Also why I used the plates. System so far has been just peachy! Have bought a couple of air staplers that use regular Arrow T-50 staples. Work like a charm with the "cheap" plates.

Leo G

Darin Cook_5

HR

I had went to an EOS Solar class at FW Webb and they were telling and show in their literature to use Watts Radiant Onix for your line set runs. You also have to piece together the whole rest of the system but that is another story. If it does indeed work, a call right to Heatway might be in order. That would be a dream to use for the flexibility.

Darin






Darin

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hot_rod

Onix for solar

From the Watts website

c. Install Onix™ in a system that will not normally operate at temperatures exceeding 210°F with intermittent exposure up to 375°F.
Intermittent in this case is defi ned as brief instances (typically lasting less than fi ve hours and occurring no more than 3 times per
year) that may arise due to system malfunction and cause stagnation. For any properly installed and maintained system, these
conditions would not be expected to occur on a regular basis.



Depends on how reliable your power is I suppose. In my rural area 3 times a month is not uncommon for power outages 2 weeks straight without power a couple times since I've been here.

Maybe a PV powered pump would be a good option, with that 3 times per year clause?

hr

Unknown

Darin, if you make that call to Watts radiant let us know what you find out.

I think Dan Chiles of Heatway still works with them, he would give you a straight answer.

Some here have said brazed joints at the collector and copper or stainless line-sets only (even pro-press is questioned by some here). I noticed that Buderus is using a "rubber" hose with spring clamps to interconnect collectors, this probably permits a bit of movement between the collectors and prevents stress from expansion.

Onix for solar ? if it's safe then the question depends what one considers a reasonable service life. While 30 year old solar systems are still operating, 25 years is a figure commonly used in doing life-cycle cost analysis for solar thermal systems.

I'm not sure given the imperative of getting renewables on line affordably that we should be insisting on materials with century long life expectancies.

Unknown

HR, do you think that current DC pump offerings are as reliable as the AC wet rotor pumps we know so well ?

hot_rod

Laing has

a new D5 Strong version out. I have one up and running on my own system this summer. It currently moves 2 gpm through 100 feet of 3/4 Solarflex without a problem.

Laing has a good reputation with that small DHW recirc, and I have a bunch of the early D-5's out there on solar installs.

Looks like their 120V ECM circ is just hitting the shelves also.

hr

Dennis Foley

Onyx in Boston

We have used Onyx almost exclusively, in many types of systems, including one with cast iron radiators that operates at 180 design that was installed over ten years ago.
We have never seen any problems with sludge, or anything else.
We have put it in concrete, staple up with foil below, on top of the subfloor similar to climate panel, and used it for high temperature distribution systems.
It is much easier to use than pex, and we have never had any problems with it.
On the other hand, we just had squirrels eat through some water pex!

[Deleted User]

Getting Hosed On Solar...

I would not do it.

One of the interesting facts we found during the GY E2 debacle was that the higher the operating temperature, the faster the product went in to failure mode. We actually had a lab in California (Failure Analysis, Inc) who did extended life failure analysis, and with the E2 they found that increasing the operational temperature of the system cause the E2 to become brittle (like glass) in short order.

One has to resist temptation, and one must do the right thing, unless one is REALLY into doing things twice, as it pertains to solar. I used PEX on my solar system as an experiment to see how long it lasted. It lasted abut a month, and I suspect it was exposed to a stagnation condition once... Sure am glad I wasn't any where near it when it BLEW. Both of my dogs were EXTREMELY skittish that day...

As I remember, E2 also had a high allowable temperature of operation. In fact, I thnk we found 2 or 3 statements allowing operation at or near steam for extended time frames...

You've all heard of NIMBY (Not In MY Back Yard...), well, NOMR (Not on MY roof) :-)

ME

hot_rod

My experience with pex and solar

was quick and to the point as shown below. I was amazed as to how well the copper crimp held, however. I still had to cut the ring to remove the pex!

This failure happened within an hour of a no flow condition on my shop solar panel.

It seems the installers are always the first to get "thrown under the bus" when failures occur. When it comes down to the court of law to whom does the liability fall when the product/application is not clearly defined?

Who is responsible for tracking events within the solar system, such as temperatures, frequencies? The homeowner?

We have seen how these thinks play out in court before.

What is the motivation to use a product with limitations like that? Cost? Installation ease?

This seem to tie directly to contractors liability insurance costs and availability

Why not just engineer the product to the application, and prove it.

hr