Which PEX brands for Thermofin-C plates

Tom Luoma

Radiant Engng sells it as PEX-c and their lit recommends PEX-c. I have the Vieage lit but can find no ref to PEX type.

Can you point to a link?

Tom Luoma

Which PEX brands for Thermofin-C plates

We are putting in our first underfloor hydronics system.
We want to use Radiant Engng Thermofin-C heat plates on 8 inch centers.

They recommend ViegaPEX Barrier (PEX-c) because they say PEX-c is gripped by the track better -- but it has a 9.5 min C/L bend radius. We find this troubling.

They have had noise problems with PEX-a from a company we don't know -- Mr Pex.

They don't sell Wirsbo hePEX (PEX-a) due to a Wirsbo selling a competing heat plate.

So the questions are --
Does anyone have experience with these plates and with whose PEX and type?

What about this bend radius issue?

Who is making good barrier PEX now?

Is there a overall recommendation?

bb_11

Viega

is not PEX-C, it is PEX-B.

Except for their FostaPEX which currently is PEX-C.

Andrew Hagen_2

Pex and Plates

Mr Pex, Pex-Aluminum-Pex works great. Absolutely no expansion noise. Unfortunately, compression fittings are necessary. Crimp fittings will not work. Pex-Al-Pex is also more difficult to work with because of the stiffness.

I believe the noise issue with Mr Pex-a (LK Pex) has been resolved through the application of a layer of PE on the outside of the EVOH oxygen barrier.

I have installed miles of Roth pex-c in Thermofin, down to 6" centers.

Andrew Hagen_2

Viega

Pex-b is cross-linked by the silane process. Viega pex is pex-b. I have found pex-b to be the least flexible of a, b,& c.

hot_rod

I like PAP

best for transfer plate application, but it does take more care to install. If you can keep loop lengths under 250' 3/8 PAP is a bit easier to work.

I've never tried Viega FostaPex. i think the extra layer around that tube would make it tough to drive into the plates. It's a great tube the best of pex and aluminum without the delam potential some PAP's experience

I think any pex with the extra layer over the squeaky EVOH barrier would work. Just allow for expansion movement if you drill the loop ends through joists, etc.

hr

Tom Luoma

Yes PAP is great -- it is all we have ever used. But we were always putting it in concrete. We still have some rolls of AlumiPEX which has always worked great.

BUT we feel putting PEX in between joists is pain enough without the extra stiffness of PAP.

I guess the main problem were having is the shift in the PEX industry since we last bought any PEX. We don't know who the reputable makers are anymore.

troy_8

Pex in plates

We prefer 3/8" for ease of installation. The 5-layer pex with the barrier inside is what we prefer. Roth makes one. Weil mclain used to have it. The barrier is the problem with plates. In/outdoor water temp. control helps. The 3/8" will go down to 4" centers quite easily. You just run a little shorter lop lengths.

Unknown

Mr. Pex stopped having noise problems a long time ago when they added another layer to their pipe. We use it routinely with no noise.

hot_rod

oval shaped pex

I heard the super flexible M Pex had some problems with it coming off the rolls somewhat egg shaped as it was a much softer more flexible tube? In some areas it fit tightly in the plates, on the narrow dimension it would fall out. Or is this just a rumor?

I recall the fit, or lack of, being more of an issue than the noise , which it sounds like all the manufacturers have addressed with the additional layer?

hr

Unknown

I don't even know how much of this we have out there now (lots), and I'm not aware of any issues with any pipe after the additional layer was added. The fit sure seems tight here in the shop.

I've seen "fit issues" with the RTI plates (joist trak), but not with thermofin. Those too were quite awhile ago so maybe RTI tightened up the tolerance, I dunno.

Jake_9

We use Watt's radiant pex never had any problem doing a 6" bend! For the noise in the staple up application, constant circulation sure does help a lot!!

Andrew Hagen_2

Oval Pex

I saw an issue with slightly oval Mr. Pex about 4 or 5 years ago. I haven't used it since, so I am not sure whether that issue still exists or not. The oval seemed to be more pronounced toward the center of the pex coil.

It was nowhere near as bad as the old RTI plates.

I think the primary issue is the EVOH barrier on the outside of the tube. I have never seen pex fall out of Thermofin, and even the oval tube seemed to return to its original shape once the system had been running a while.

Tom Luoma

Wirsbo, Mr Pex or LK?

Is Mr PEX w/O2 actually LK for sure and not a copy made somewhere else?
The LK (ThermaPEX) seems to go for a lot less.

Do they both and Wirsbo hePEX Plus have the extra PE layer?

Given price/performance which of the three to use? What if price is not an object?

LK $360/1000ft
Mr PEX $500/1000
Wirsbo $600/1000