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3/8" aluminum pans? [and 3/8" manifolds for that matter]

might have tried this once already but forgot to subscribe to the replies and lost track of the thread.

[Dan, is there a way to just automatically subscribe to any thread i start or post on?]

So the pricing is very competitive these days for 100 count boxes of 1/2" staple over -plates.  the lighter kind that go up under the pipe rather than have the pipe snap in.

but i am having a very hard time finding affordable quantities of 3/8".  It is so much niced working with 3/8" tube, i don't mind shortening the runs a little bit and adding a manifold or two [ which is only complicated by the fact that manifolds have gotten very affordable but not in 3/8" size so I have to crimp a short piece of half and an adapter on all my manifold inputs]. 

Am i the only one who likes 3/8" so much or is there a place to get any of this stuff?




  • WeezboWeezbo Member Posts: 6,232
    3/8 th's ?

    why not use pex -a Rehau , Wirsbo ? isnt that good enough ? long time back Stadler made some too i think it was 10 mm or something like that..

  • archibald tuttlearchibald tuttle Member Posts: 484
    are you talking tubing or heat transfer plates

    i see manufacturers names but not sure which product you are referring to.

    i've got lots of 3/8" [nom, 1/2" OD] tubing already.  use it regularly for small slab work and making my own patterned foam floor grids out of xps foam with a 1/2" box core bit.  i've got heavty industrial foil i use for heat transfer in those applications .  just lay across the routed groove and press the tubing in. voila.

    i'm looking for the relatively inexpensive aluminum plates made of maybe .011 or .014 aluminum flashing that go up after the pex.

    i don't know if rehau and wirsbo have this approach but they sound expensive just by having brands names.

    you can get 100 pcs. formed for 1/2" nom tube of generic aluminum flashing pans 2' long for $116. and 1/2" tubing isn't really any more expensive than 3/8". but the 3/8 is so much easier to work that if i could get pans that fit it, i'd be all in. 

    so far as i can see, it is just a unit thing.  everybody uses 1/2" so that is what you can get.  just hoping that there are a few other 3/8 lovers out there like me and there is actually a source.  i'm not looking to get stuff cheaper than 1/2" but similar or not too much premium would ge tit done for me.

    if there is something specifc in rehau or wirsbo i should look at let me know.

  • JeffMJeffM Member Posts: 159
    Viega 3/8"

    Viega offers the thin staple-up plates in 3/8" size, stock code 15205. I agree with liking the ease of working with 3/8". There ought to be other manufacturers producing a plate in this size, but I haven't searched.
  • archibald tuttlearchibald tuttle Member Posts: 484
    edited January 2014
    i like 3 per at 3/8"


    thanks, i just found those veiga plates on amazon but they are 19" long not 24" and they are $215 per 100 pieces and they are out-of-stock.

    i just think manufacturers are ignoring the possible utility of 3/8 because the industry has chosen -- maybe by default - to standardize on 1/2".

    also, try getting a 3/8" manifold, as i mentioned in the original post.

    it is hard to find the 3/8 pans period, (and searching for fractional things is always difficult anyway, did you mean 3 - 8 ft. something or others, and you can't put in the  inch mark, " , as it may be interpreted differently etc.). i've searched on numerous occasions although now that i got interested again, i answered my own question this morning and believe i have found one cost effective supplier.  see Blue Ridge Company :

    i'm of course interested in experiences pushing the limits on 3/8 loop lengths, etc. right now, most of the ones i have operating are 100 ft. in small bathroom, laundry room or small bedroom applications because i inherited about 50 rolls of 3/8 pex x 100 feet.

    But i'm starting to run out of that stash and so i'll be buying longer lengths.  if i buy 500s i could cut them into 2 250s..   That is the max recommendation i've seen.  or i could buy 1000s and cut them into 5 200s.

    As far as application goes, I tend to find that underfloor does better with three passes per bay which i just find way easier to wangle with the 3/8.  of course you get a little overlap of the plates at 5" but finally finding the plates for a decent price that still can be done for about $2.13 per square foot  in materials at three passes keeping the install under $5 a square foot if i don't try to pay myself too much for my time . . .

    i don't know how much of this stuff will be at AHR next week but i'm going do some more due diligence, i.e. drinking beer and lookin for freebies, and will report.

  • SWEISWEI Member Posts: 7,356
    Watch your head loss

    100-150' makes for easy pumping.  Keep as many loops as possible within 30-50' of each other and system balancing becomes a walk in the park.
  • archibald tuttlearchibald tuttle Member Posts: 484
    150' is SWEIt spot?

    if i read this right.  i try to balance leg length even coser than that, although i guess if i were being really tricky i could use longer lengths at the center of the rooms . . . and shorter at the outside a minor space balance.  but iwith underfloor being mprisoned by joist cavities you don't really get theflexibility in pattern design when you are running over floor or in a slab so i think i'll probably just go even legnth as you recommend. with all the manifolds on one side and 6 25' joist cavitiies covered for each 3 150' lengths.   those sioux chief manifolds are pretty damn affordable and i worked out a great pattern based 2 sets of 3 passes per bay per third of the house, which effectively defines rooms. although it splits east west, not north south. but i can cover this with 6 port manifolds and give myself some sectional balancing, esp relative to the center third which has more limited exterior exposure.

    as an aside, who has a good method for heating a cast iron tub from underneath.  it is already in place, but i have good access underneath.  when i can flip them upside down gravity and access help so i can wind maybe 20 coils of tubing bedded in a high tech thinset and then foam the assembly but i've never tried from underneath.  i could try a really dense wind on a piece of plywood with may be a2x4 lip, support it under the tub and fill with concrete. that would heat the very bottom, but maybe conduction would get me what i need from there.

  • SWEISWEI Member Posts: 7,356
    Sweet spot

    depends on flow of course.  Uponor ADS allows me to slice and dice until I get the flow and head to make sense.  It's common to end up with one or two loops which push the head requirement up by 2-4' -- I try to re-arrange those when I can.

    I've tinkered with heating CI tubs as well.  No easy way to route and secure around the back (or the flange side) of an existing tub.  Filling the voids with blown cellulose helps, even without direct heating.
  • ChrisChris Member Posts: 3,056
    edited January 2014
    I Beg To Differ

    The industry standard has never been 1/2" going back the late eighties, early nineties all we used was 3/8" and 3/8" plates. The #1 reason contractors use 1/2" plates is that they think they can get more btu/hr out of 1/2" then 3/8". Most also combine rooms in loop lengths in joist heating applications, they like to max out at that 300', less manifolds.. In the end its all about cost.

    Those cheap tin plates suck, you still need to leave a 2" air gap between plate and insulation, they tick, tick, tick, you end up with higher water temps as well as uneven floor surface temps. You're still relying on convection in the bay to produce the btu/hr the floor needs.

    With the nice extruded alum plates, such as, Joist Trak or Climate Trak, you can insulate up to the plate. Your heating transfer is direct plate to floor, no noise. Allows for lower water temp, less noisy systems, faster response time and a better distribution of even floor surface temp.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • archibald tuttlearchibald tuttle Member Posts: 484
    but we're already at $5 a sq. ft. on the cheap

    and those extruded beauties almost double that.  i get that they encourage better contact with the pipe by their heavier snap in design but on the several jobs we've done we've gone with the silicone caulk in the pans and we get a little warm up noise but not too bad.  we developed a method for taking large jawed nail pullers/nippers and crimping the pans around the pipe after putting in the caulk and used 4 screws per pan.

    modest bit of noise but quieter than baseboard and my friend actually still runs that house on a thermostat.  how much noise is there going to be slowly changing temp over a range of maybe 20 degrees?  maybe i underestimate that as a problem but it hasn't been too bad with thermostat style on off so i hadn't been worried.

    we didn't put insulation on that job, but what would really be the problem insulating right underneath these pans? do you have to run the water hotter or . . . .?  esp. where i'm moving my design up to 3 runs of 3/8 with stamped pans per joist cavity i don't think i would have too much need for hotter water than 2 runs on the extruded style but i can't say that from side by side comparison, i'm planning to spray foam underneath so this is my own place and it can be the acid test.

  • ChrisChris Member Posts: 3,056
    Those Plates

    Are also 4' pre drilled and ready to go. What's it costing you in time to fool around with those out of date plates and getting them installed? You do factor that cost in right? As for the insulation. You best be leaving an air gap with those flimsy plates. You need convection to drive the heat transfer. Lower the convection you lower floor response time, ruin your chance at even floor surface temp and could possibly even not be able to reach set point.

    You didn't put in insulation?
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
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