What I found out about Onyx

leo g_13

looked into the thing about using plates with Onyx. Having been in the pex field before being hired by Watts, he couldn't see why plates wouldn't help the Onyx. Well after talking with the Watts engineers, he relayed to me their reasoning for no plates. According to their in-house testing, plates only add about 8% more efficiency to the Onyx when it is stapled directly to the sub-floor. They feel that for the added cost of the plates, it is not worth it.

By the way, their testing also indicated that the plates on pex, increase its' efficiency by up to 25%.

Leo G


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ALH_3

Plates

Which plates? How did they test? By efficiency do they mean output?

From what I know, the reason for no plates with Onyx is more of a dollar issue than a performance issue. In fact I believe Onyx with plates would have lower performance than pex in plates due to the thick wall of the Onyx tube. So then why not just use plates and pex for less money and more performance? Watts doesnt want to obviate the Onyx tube.

-Andrew

Mark Hunt

Telll ya what

I've got miles of onix tubing installed out there and I have NEVER had an issue with a system not performing. Maybe because I do my math?

This subject has been beaten to death. If Onix didn't work then I should have frozen years ago and I should have been sued into oblivion. Neither has happened yet sir.

I can tell you that my kids LOVE a warm floor! You think they know that there are no plates there?

There is a big diference between what you think and what I know.

Mark H





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Rookie

Onyx is great

Bravo Mark !! I get so tired of reading these anti-onyx post, it is a great product,easy to install.My six month old daughter Caroline is learning to crawl on an onyx heated floor!

Constantin

However,

I presume that part of the reason that Onix has worked as well for you is that the systems as a whole were well-thought out in advance... that is, matching the heat loss was not impossible because the home had adequate insulation, etc. In the wrong home, no form of radiant floor heat will function properly...

So, for me the issue is not what tubing is being used, rather it's whether that tubing and/or plate combo can get the job done. Presumably, Onix works great in homes where heat loss is a bit more limited... higher-loss areas would benefit from more efficient transfer mechanisms all the way up to bare concrete, right?

Boilerpro_3

Right on, Mark!

I have used both, and I am leaning more and more to using Onix. I would have used it recently, however, the heat output was going to be too high for many spaces, so I used suspended pex instead. Maybe next time I'll use Onix for most of the job, and take care of a few low loss rooms with suspended Pex.

Boilerpro

Steve_35

What sq ft output do you get with Onix?

jwade55_3

My 2 Cents worth

As Mark said, doing the math makes a big difference. I personally have only been involved in 200-250 radiant projects using Onix, so not sure if my opinion counts, but here I go. What I have found is that there are very few projects, and typically only isolated areas within the project, that a correctly installed Radiant panel consisting of staple up Onix cannot heat. And most of the time the reason we cannot heat it is lack of effective floor area due to obstructions. In my own house my family room has a pretty high heat loss(roughly 33 btu/sq ft) lots of glass, lots of exposure, and is heated soley by the onix staple-up, and believe you me if it wasn't warm my lovely fiance would not be so lovely.

Now my master bath is a different story, heat loss is around 25 btu/sq ft, two outside walls, large windows, but the effective floor area would require almost 50 btu/sq foot, and my surface temp would exceed 85 deg, so I installed a supplemental radiant panel, nice warm bathroom.

What I find is that by doing the math, zoning properly, addressing area of higher heat loss with the proper heat emmitance devices, projects work.

I have designed pex w/ plate systems as well as Onix systems, and have had to do the same type of auxilary heat sources in both types of systems. At the end of the day, if I can give someone a system that will heat efficently and properly, and allow the installer to do it as easy as possible, while still staying cost competitive, I'm happy.

J

Andrew Hagen (ALH)

Math

First of all, don't make assumptions about what I know.

Second, I never said Onix doesn't work. That's not even the topic of this thread. The subject is whether plates make sense with Onix tube. I stick by my statement that Onix with plates will not perform as well as pex with plates, but it would certainly heat a home. Lots of things will heat a home. It's the economics that would likely make it a foolish decision to use Onix and plates.

The math proves my point.....thermodynamically and economically.

-Andrew

Andrew Hagen (ALH)

Andrew Hagen (ALH)

Dale Pickard

plates

Mark,

You are not defining performance. Performance = btu per sqft per deg-dt (water temp - floor surface temp). Our extruded plates with rubber or plastic will outperform either system without by a wide margin. Just because you can satisfy a Tstat setpoint with high water temps doesn´t mean the staple up systers perform. Try limiting your water temps to 120f and see how well your staple ups perform.
Staple up is an idea whose time has come and gone. I know you think hose clamps are cool but their not.

Dale

Dale Pickard

Gee mark,

I didn´t know you could do math. Likely, you just run computer software that you don´t really understand, right?
ALH has a degree in mechanical engineering and A LOT of field experience with radiant floor heating.

Dale

Mark Hunt

Dale


We limit our water temps to 130, after that the room gets supplemental heat.

Plates obviously increase the conductive area so lower water temps can be used, no arguement there.

Mark H

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Mark Hunt

Sorry Andrew


My post was not meant as a shot at you, but it definately came off that way. I apologize.

WattsRadiant(Heatway) says that plates are not required with Onix and I have never used plates with it. That being said, adding plates would be similar to doubling your tube spacing. If you were to run Onix 4" o.c you would see that lower water temps could be used to heat the space.

Of course you would be doubling the amount of tubing on the job as well as the labor to install it. That would probably price us out of the picture.

I have never seen any information regarding plates with Onix so how it would compare to Pex I can't say.

You may be right.

Mark H



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Mark Hunt

Are you trying to get another customer Dale?


Thanks for helping me make my decision on where NOT to buy the plates for the job we are starting next month.

Mark H

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Troy_3

Settle down boys

Obviously a nerve has been struck. Let's state the facts. Rubber transfers some heat. Not as much as pex at any given temp. Extruded aluminum plates increase the energy transfer a Lot. Anyone can attest to that if you have used them. Providing comfort at a lower water temp. decreases the cost of operating a condensing boiler. Therefore even a simpleton like me who doesn't have all the answers can conclude that pex and plates or rubber with plates( if there is such a thing)will work better than without plates. I can't comment on how much better plates improve rubber. The issue that gets me going is to state that rubber will transfer as energy as efficiently as pex and tube. That is simply not true. Go ahead and use rubber if it fits your load requirements. Just be honest about why you do it. There is nothing wrong with ease of installation. It may reduce installation cost. But don't start confusing that with "It just works better" Cause it doesn't! Just my 2 cents. OK call me a Dope! It my turn.

Darin Cook_3

Constanin hit the nail on the head

Do your homework. If the floor output will not heat the room then you need supplemental. We have miles of onyx out there. No complaints here. Pex and plates are a excellent way to heat a home. Payback and cost of operation is between you and your customer. The plates are expensive as you all know. They definetly have their applications. So does Onyx. I have yet to see any of our customers ever complain about being cold or problems with flooring related to our installation. The max temp on our designs on design day is 130'. With reset, that temp drops much lower in the shoulder seasons. If you can sell plate jobs all the time then run with it. It is a great way to heat a home. Hands down you can run the lowest water temps than any other design. Is that always worth the extra material expense and labor? That is once again between you and your customer. Fighting over different install designs really is not the issue. It is how often every day that ^%&%** systems go in with no design and the ugly mark it gives to all of us who give the extra effort to ensure our customers comfort and energy efficiency!








Darin

Tom_35

Onyx has it's place---

We have very few basements in our area, so we don't have the luxury of standing up to install our piping. There have been jobs where pex and plates would have been dang near impossible to install while the Onyx went up fairly quickly. The labor would get to an economics issue in a hurry in one of these situations.

We too have not had any problems with the performance from Onyx and 130 is our top temp as well. I've noticed jobs where Dave Behler and hot rod have both used Onyx and feel that if it wasn't a good product that these pros wouldn't touch it.

Concerning plates, we are finishing up a job with the Radiant Engineering plates purchased through Watts. The difference between these plates and the plates we've used in the past is night and day. I chose them based on info from hr and don't think we will be disappointed.

But---if I was a supplier/manufacturer of radiant products that provided materials to legitimate contractors, I certainly wouldn't be slinging insults at my "client."

My opinion---

Tom A

ALH_3

Method

There are all kinds of opinions about various radiant heating products. From boilers to tubing to controls, everyone has a preference. Some things, like boiler brand, are based more on a Cadillac vs. Lincoln preference. Different manufacturers arrive at similar places in very different ways. Even at that, there are still Yugos in the boiler marketplace to this day. (I won't mention Raypak's name)

The same is true of tubing. Whether you use Brand A or Brand B is not as important as how you use it. Onix is the tubing of choice for staple-up jobs. It solves many problems that staple-up pex had. EPDM is amazing stuff. Without hard data I would speculate that staple-up Onix performs very similarly to staple-up pex. Onix simply wasn't meant for plates. With plates the issues with staple-up are solved, so there is no need for the rubber tube. Both staple-up Onix and pex w/plates solve problems with staple-up pex. There are output differences, however.

I would very much like to see an independent study of all the different installation methods available today. Compare Thermofin, Onix, staple-up pex, Ultra-Fin, Quick Track, Warm Board, Climate Panel, Sub Ray, Rau Panel, and the others. There are so many different products that I have trouble keeping track of which is which. All of these methods have limitations. Some have severe limitations. Presumably the RPA is there to do this, but I have yet to see them say anything doesn't work well. Not every idea is a good idea. I am tired of the misinformation in the advertising for certain products. There's no real accountability. It's frustrating to see Thermofin rated for real-world conditions, while Ultra-Fin is rated for pixy-land conditions. Something doesn't add up, and someone's home isn't heating like it should.

There are in-betweens also. If performance and output were the only concerns we would all use Thermofin with copper tube. That's a labor intensive install. Certainly not all jobs need high outputs, and it's every installer/designer's responsibility to recognize when.

Plates greatly help pex, as they would Onix. But that's a perversion of the original intent of Onix. Onix fills a niche. I just prefer to let panel radiators fill that niche.

The longer I spend on The Wall, the longer my posts become. Maybe it's contagious.

-Andrew

hr

I'l challange you on that, Mark

that 4" oc Onix would perform like transfer plates? Building an EPDM transfer plate (*Onix 4" oc) will not give you either the heat transfer contact patch OR the conductivity of the aluminum.

By Watts own calcs you can see the "hit" you take when you use EPDM rubber as a conductor of heat.

I do agree that EPDM can and does work. Very little error room when the design calls for 160- 170° supply temperatures. And contact with wood surfaces at over 140°F really isn't accepeted by any of the wood testing and listing labs.

Knowing when to hold em and when to fold 'em is the key

hot rod

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Mark Hunt

Whoa


I said it would be similar not the same. By concentrating the tubing in an area you are in essence creating a larger conductive surface.

I do not mean to imply that it would equal plates.

Mark H

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hr

I know, Mark

you used similar, not same. But define similar. 10% 20, 50% difference? That's the number that eludes us all when trying to make the comparison discussed here. How close is close. Without a tight number this is where the "underheaters" get in trouble, I feel.

Pushing the output numbers too tight and not having any wiggle room should the building not turn out "exactly" as the plans had indicated.

I recall a Watts Radiant engineer telling me tighter than 6" oc you are wasteing rubber money. If the panel temperature can not meet the load with 6" on center spacing, you are not going to get there with one more hose squeezed in.

I haven't checked lately does the Watts Radiant Works software go down to 4" oc design ability?

hot rod

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Mark Hunt

Honestly


4" o.c was really only used for banding exterior high-loss areas, but it really didn't help much even according to Heatway's software.

My point was that doubling the tubing would not get you to where plates would get you and the cost would be extreme.

And even if you could do a 4" o.c install, it won't help you when the heat loss exceeds the effective floor output at max design temp nor will plates.

We design around a 130* max water temp.

We will be installing a full plate system with a small area of Quik-Trac next month. Temps will be way down not just because of the plates, but also due to the construction of the home.

The homeowner is an engineer with a HUGE company in the area and he specifically asked for this system. He understands the relevance of lower water temps, but he also knows the importance of keeping his btu requirements to an absolute minimum. That is the golden key to a truly energy saving home.

Mark H





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Dale Pickard

Not a problem Mark,

Hard to imagine what its worth but I can´t lose something I never had, eh? I guess we´ll just have tostruggle along without you. Anyway, if you keep calculating long enough, I´m sure you´ll find a way justify what you would prefer to do anyway.
Good luck,

Dale

ScottMP

Andrew

What are the " many problems " that staple up pex had ?

I understand flexabilty , what the are the others ??

Scott

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Weezbo

Wow.....

it is interesting to me that so many people find they like a certain product know how it preforms and could basically care less what some or any other system offers....you wouldnt ever see Me being irrational about my favorite boilers,or pex,or injection system...

Mark Eatherton1

Splain this Lucy...

My good friend and anal German hydronics technician Richard Graves tells me that the Onyx tubing systems he sees in the field make a sound like someone stepping on Rice Crispies when it is moved? Is this "normal"? He also tells me that he keeps getting black rubbery gunk when he goes to flush the system. Is flushing these systems to induce cleaners and corrosion inhibitors the wrong thing to do?

I hate to raise questions about products like this, but I think it is my duty to raise concern before we end up getting into another tubing failure debacle, and I realize that the poly tubing on the market is not perfect, but my gut tells me to avoid rubber based/type products. I've had ONE vehicle that I didn't have to replace the rubber cooling hoses on, and that was a 1969 Volkswagen bug...

I personally hope my anal German friend is wrong, but he's never been wrong in the past...

Comments anyone?

JMHO

ME

Mark Eatherton1

By the way...

During my tenure with a previously unnamed employer, we did come upon a situation where the only way to drive enough heat through the 3" of soft wood flooring we had was to utilize Xtruded plates. It was a **** to drive the 3/8" hose into the plates, and the crew threatened myself and the owner with a loss of life if we ever decided to take an orphan system like this on again... But it DID work.

It falls along the same lines as grooving concrete after the fact to install radiant. Most people will try it once, but NEVER again...

ME

Boilerpro_3

Water Temps and Efficiency

I suspect few would disagree that lower water temps equal better system efficiency. Even with a conventional non condensing boiler, lower water temps can reduce distribution losses and produce some boiler efficiency gains.

However, with a condensing boiler the savings by designing to lower water temps would be much greater. The question is how much?

When talking efficiency, I really do not worry about efficiency at design outdoor temp, as long as it heats adequetely is the main issue. Efficiency really matters for that 90% of the heating season when you are at only 50% to 60% load or less. For my -5F design temp, that is about 20F outdoor temp.

I use this design point in all my heat load calculations for larger heating loads and have traditionally recommended staged boilers. Using staged 80% boilers with good controls vs. large single input 85% boilers usually cuts fuel usage from 40% to 70%.

It also makes sense to me to use this same design point when looking at system water temps and the use of condensing boilers.

I'll use my own home as an example. The system is predominantly standing radiation sized for 160F supply, 140F return (150 design), with some Onix radiant floor and convectors in a few places. The house is generally well insulated (R-19 walls and ceilings, most windows and doors (original with rather poor aluminum storms) are weatherstripped and extra care was taken to tighten up the interior side of the envelope to cut air leakage during the nearly gut rehab restroration. There is a substancial amount of solar gain since the glass area is about 25 % of the floor area and much of it is on the east and south sides.

Now if you figure you are at at most 60% of design load for 90% of the heating season, and account for internal gains like people breathing, frigs running, etc., you probably need only about 50% of design output for 90% of the heating season. For my 150F design system, that would be 110F average water temp on the typical day. Assuming a system designed at 20F delta tee at full load , and we are at half load, that would be about a 115F supply and 105F return. I've been running with a 120F setting on my aquastat, and a 20F differential for a month now and the thermostat still cycles some even when the temp gets into the teens.

Now if we take that same system and design to 130F supply, 20 differential at design (120 design temp, on that 50% load day you would have 95F design temp, 100F supply and 90 F return.

Now what is the efficiency difference at these two boiler operating temps? Both are running the complete boiler heat exchanger at condensing temps. I also suspect you could run a little higher system diff on the higher temp system and need a little lower temp diff on the lower temp system for even comfort.

I suspect the efficiency difference is only a couple of percentage points at most. When running my Dunkirk Quantum Leap 95 at the above described conditions, and checking at the air intake and exhaust pipes, the efficiency on my analyzer moves up and down about 0.2 % above and below 98% depending on boiler temp, with 8% excess air running through the boiler (still need to work on that) and an exhaust temp of 85F. I suspect a standard condensor would be about 3 to 5 points lower.

The point is: Is it worth spending thousands of dollars extra on a system to get absolute minimum water temps to only pick up a couple percentage points in efficiency? I suspect, that it would be better investment to upgrade that condensing boiler to a condensing/recuperative model, and even that may be questionable.

Just some food for thought


Boilerpro

hr

I can't understand

for the life of me why the sales staff at Watts Radiant is so against offering Onix transfer plates.

With a plate option the choice is completely up to the HO or contractor. And many, if not all, of the under performing rubber systems (for whatever reason they underperform)could be upgraded without a complete make over.

Seeems to me like a win win. Fixes are possible and Watts has anoither "profit center" in the plate department. they now offer the ThinFin in their lineup, they are so, so close to that final step

As to the rubber flakes, yes I see them in Onix systems also. Not sure they pose a threat if they stay in suspension and do not plug mix valves, strainers, etc. Probably a good flush and hydronic cleaner at start up would make this go away?

hot rod

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ALH_3

Problems

Staple-up pex had problems related to contraction noise and "ratcheting of the tube against the staples. These are the problems that Onix addresses. Plates address these problems but also address the heat delivery and high temperature fluid inadequacies associated with the staple-up method.

At least those are problems in my book. No doubt they can be overcome with supplemental heat also.

-Andrew

Boilerpro_3

Oh course, the plates also contribute to noise

which still tends to be a problem, even with reset. Oinix is silent.

Boilerpro

ALH_3

$$

The whole theory of plates is to extract as much heat from the fluid with the lowest temperature drop from the fluid to the surface of the floor. This allows the boiler to work much more closely with the heated space with minimum lag. This can only provide a more comfortable home, and with modulating/condensing boilers we now have the ideal tool to make Thermofin work the way it should and vice versa.

Will the fuel savings make up for the additional cost of Thermofin, Warmboard, Quick-Track, etc.? More than likely, no.

Will staple-up perform to everyone's satisfaction? Definitely not. Hot Rod's IR photos prove that beyond a doubt. Is staple-up "good enough"? Not in my opinion, but I'll stress that's my opinion....though it is shared by many others. I don't look at the money spent on Thermofin as "extra". I view it as necessary.

Will a water heater result in the same warm home as a Vitodens? Yep. What about a Munchkin and a Vitodens? Also yes. You still have to admit there are tangible differences there. People are willing to spend more for those differences, and they aren't always the people with the most money in their pockets. In fact much of the time they aren't. The same goes for the use of plates.

It all boils down to what's important to the customer.

-Andrew

ALH_3

Noise

Plates can make noise, and I'll stress that Thermofin has far less tendency than the knock-off's. If the correct materials and installation methods are used, plates make almost no noise. Thermofin plates do not contribute to noise, they control it. The others (wirsbo) may actually contribute to noise because of the less than tight fit.

But yes, Onix is silent. No argument there.

-Andrew

Boilerpro_3

Agreed,

I was especially responding to the many that say that suspended tube, staple up, or higher temp systems in general are not truly compatible with condensing sources. The typical response seem to be that the customer will take a big hit in efficiency unless you use plates.

I like your point about response time. However, when using tight outdoor water temp reset, response time starts to disappear....the system will respond very slowly wheather using convectors, standing radiation, or radiant floor with plates. If there is a large sudden drop in indoor temp, more direct coupled systems will definitely outshine suspended tube or slow response systems (such as standing radiation). I believe in most homes, however, this is largely a non issue, but maybe I'm missing something. I suspect if you have lots of solar gain, this is one place plates will shine.

Boilerpro

leo g_13

Hey Prof,

what I found out about this generation of Onyx is that it is cross-linked like pex now. I can't recall the exact name of the material, BUT it is definately NOT the same as the rubber you find in rad hoses! As with pre-fabbed panels, I will use this product where it lends itself as the better way to go.

P.S. - I just posted this "stat" that my Onyx rep was able to find out for me, just as general knowledge. I approached the project we were on with a "plates or get someone else" attitude.

But now knowing that plates have only about an 8% effect on the Onyx install, then next time I will have to figure this into my decision.

Though personnaly, I still feel that 8% is a great advantage for overall system effeciency.

Leo G

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leo g_13

hey Andrew

for the job that I am presently using the Onyx on, in my opinion, it was the most economical way to go. This house has 4 different levels on the main and 5 levels on the top. To try to pull pex, or use lengths and couplings on this job would have been a labour nightmare! The onyx was just to slick not to use!

Leo G

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