Hi all:Still building my new house,and thanks to some good advice here(Thanks Piff) I will be installing a manifold system with (home run supply lines) for the domestic hot and cold water lines(some pex/some copper)My question is: in several of the pex manufactures manuals I have they recommend 3/8″ pex to the low flow fixtures 2 1/2 gpm or less(lav,kitchen sink,some toilets) the reasoning is ,that the wait time for the hot water is reduced when compared to 1/2″. Which in the long run should save water and energy. Friction loss is not supposed to be an issue as long as your not over 80′ Have or do any of you guys RUN the 3/8″ supply lines? or just say the heck with it and run the 1/2″
Also while I’m at it do you buy your manifolds(what brand and diameter)or make them up in the field
Thanks Greg
whoops lost this post I’ll try again
Edited 3/15/2004 7:03 am ET by GREGGO10/2 10/3
Replies
For domestic service, my preference is to run the same size PEX that you would if you were still running copper.
For hot water, it's often better to adjust the design instead of choking down the pipe.
You can easily make your own manifolds and mini-manifolds from copper.
I'm not a plumber, but I've never heard of making you own manifold. Is it cheaper? Better quality? I've seen inexpensive plastic ones for pex, and also some much more expensive brass ones as well.
How do you make one?
For domestic water manifolds for PEX, it's quite simple. Just sweat it from standard copper tubing and fittings. Add in valves w/ or w/o bleeds as required, where required, so you can shut down portions without having to drain the entire run.
I'd say it's less expensive and you'll usually get better valves on a home-made manifold...but more important to me, you can get the valves where you want them. Plus, you can make it as large or small as you need, with provisions for adding on in the future.
For RFH I use manufactured manifolds.
"For RFH I use manufactured manifolds."
How come? Less labor? Special fittings proprietary to the ZV manufacturer? Pre-assembled flow meters?
Seems like if you could put together a potable supply manifold, given the right line to supplies, it would be less expensive to DIY a RFH manifold.
Edited 3/16/2004 10:35 am ET by johnnyd
I could certainly build one, but here's whey I use RFH manifolds from the manufacturer:
1) They are easy to assemble on-site, and adding or removing a loop is a solderless job. This can be an asset when adding on a valve in the future, as there's not a need to sweat copper on the manifold to add the additional loop.
2) The fittings to attach the PEX to the manifold come with the manifold. Easy, no extra tools required.
2) They come with built-in burp valves to remove entrained air.
3) They come with temp sensors (to feed back to the control box) and dial-read thermometers (for an eyeball reading at the manifold) to sense both the supply temp going to the manifold and return temp coming back to the manifold from the runs of PEX.
4) Each loop segment has a built-in manually operated balancing and shutoff valve. Depends on the manufacturer, but this valve can be used to tweak the flow through each valve to balance the system, or shut off heat to unheated/unused rooms.
5) Each segment also has a built-in auto-drive valve that can be connected to a motorized drive. It's similar to the previous manual balancing valve, but this one is designed to be coupled to a drive motor, with the motor position dictated by heat demand in the room. It allows a t-stat to demand heat and really tweak the amount of water allowed onto the loop. That's a level of control that's hardly ever needed...but when it's needed, it's there. If you don't opt for this level of control, the valve is positioned and left in the OPEN position when you assemble the manifold.
All the above is great if you need a highly-controlled RFH system, or if you want the capability to do so in the future. Not all are that way. If you have a basic RFH set-up, and the manifold is only going to be used for distribution, then by all means, you can very easily assemble your own manifold using the same simple copper pieces that are used for a domestic water distribution system. I'd still put a valve for each loop, though, or a valve for each set of loops that feed a particular room or zone.
I'd venture (read: guess) that the price difference between a bells-and-whistles commercial manifold and a simple home-made distribution manifold with a simple full port valve would be about $10-12 per loop. That's a materials cost only. Obviously, the home-made would require more labor, but labor cost isn't a concern for a DIY homeowner. Plus, it's highly unlikely that a DIY would use all of the bells-and-whistles, so they'd not be needed in the first place.
I'm sorry if I missed it in the earlier posts.
(Mongo)
Which brand manifolds (such as you describe) and pex tubing do you prefer ?
Not seeking an endorsement but just a starting point because I have come across or received literature on many manifold systems touting various advantages but they all seem similar in concept.
So it would boil down to service and availability for my area.
I'm particularily interested in the dial-type analog inline temp monitoring for different lines.
I've priced various options and sources on these gauges and pots (is that the correct term?) and it may be less trouble getting this pre-configured.
Thanks.
If you're looking for a manifold that is easy to assemble and where you can choose the features that you want a la carte, look at HeatLink.
It's a very good product at a fair price, and it's modular in nature. Have 8 loops? Then order the basic manifold set plus enough sectiond to end up with 8 loop kits. Snap them together, and they're held together with threaded rod. Need to add on two more loops later? Undo the threaded rod, snap on two more loop kits, then reset the threaded rod. Easy.
HeatLink does offer the dial indicators and manual air valves as well.
Wirsbo has a full line as well.
Locally I can get HeatLink and Wirsbo, as well as others, but those are the two I've stuck with.
Wirsbo has spent big money on advertising, as such they are the most common name out there in RFH.
For tubing, you're probably aware that PEX comes in three forms...PEX-a, PEX-b, and PEX-c. The "a, b, c" designators tell how the PEX was crosslinked. Some methods are better than others. Ask before you order. Generally, PEX-a (or engel) is consdered the best and most completely cross-linked, PEX-b (silane) is the worst, or the least cross-linked. PEX-c is similar to -a in quality, but again, -a is, in general, the most common PEX out there.
You mentioned (I think it was you) that Stadler had a "different kind" of PEX. I've not used theres but I do know that they have (according to the trade stuff I have, going from memory) two kinds. One is a basic PEX, black (to eliminate light transmission) in color. I don't know how it's cross-linked, but I'd venture it'e Engel. The other has an Al layer in it. The Al layer eliminates light transimission, helps control pipe expansion/contraction, and helps the tubing hold its shape when bent and set in place.
One of the reasons I use manufactured manifolds for RFH is the a la carte ordering menu, and the ease of ordering what you need and assembling it. It does cost a bit more up front, but it saves in time/labor/headaches in that you don't have to try to cobble together what you need from off-the-shelf parts...if you can find the parts to begin with. It may only run you an additional $75 to $100 per manifold. Yeah, that's a chunk of change...but it'll save you many hours of labor and head scratching.
Mongo -
Thank-you very much, especially for the HeatLink info.
Just got off the phone with the Wirsbo rep for our area and got the rundown.
It turns out the local plumbing house I deal with is the area source.
I was also steered to Wirsbo's engineering department for layout plans, etc.
I appreciate your very fast reply !
Hey Mongo:The Stadler Pex is (Cross linked polyethylene)PE-HDXc /electronbeam cross linked(say that 5 times fast)
Guess it means its pex c
Have you ever worked with those Manablock manifolds?
They look pretty interesting
Hey, keep this up and you'll be ready to write an article on PEX pretty soon.<g>
Yup, the radiation method is indeed "C", that's where the freshly extruded tubing is bombarded with the good stuff. Peroxide is "A", that's commonly referred to as the "Engel Method". With "A", they add the components and the crosslinking occurs during the hot melt extrusion phase. Little known fact, Andy's residuals and royalties finally reached the point where he could leave FHB and live the life of a country gent.<g>
In a chemical bond sense, "A" and "C" are pretty much equal in terms of how the PEX is cross-linked. Still, "A" does the crosslinking while the material is in a melted, liquid-stage, and "C" does the cross-linking after the material has been extruded and cooled a bit....at a lower temp than occurs with "A". The chemical engineer in me says that you'll get better performance from "A" than "C". Will the differences be noticed in a RFH package running at 12psi and 120 degrees? Likely no. Still...<g>
"B" is silane. when the tubing is manufactured, the level of x-linking is relatively low, it increases as the tubing is exposed to heat and humidity. In a sense, it's considered inferior to the other methods. In a sense.
Never used Manabloc. I'm pretty sure that's put out by Vanguard, right? I don't know anyone who has used the Manabloc, but I remember a poster using Vanguard PEX and not being happy with it at all. Vanguard PEX is silane, or "B". The Manibloc system may very well be a fine way to distribute water...I just can't offer first-hand advice on it.
For what it's worth, Wirsbo, Rehau, and Heatlink are "A". Vanguard is "B", and Stadler is "C". Still, blanket statements can't be counted on. Example, Heatlink makes several types of PEX. their "A" is, in general, used for domestic RFH and domestic water applications, they make a black "C" with UV inhibitors for snowmelt applications.
Now you're probably ready to go back to forced air, eh?<g>
re - Now you're probably ready to go back to forced air, eh?<g>
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When donkeys fly....
No forced air for me
I'm trying to figure how to do a sleeper system(something similar to climate panels or quick track.)I have about 60 sheets of 1/2" plywood & 70 sheets of 3/4".I'm trying to figure out if aluminum roof flashing would do for the heat transfer(and how to attach it to the floor,also how to keep the pex secured to the aluminum.I love to rack my brain on stuff(LOL)
Stay Safe Greg
It's really not that difficult.
Today's tight constuction makes it fairly easy (for someone competent) to cobble together a fine RFH system.
It's easy to fashion a jig to bend the metal, and although Al flashing isn't as malleable as the fancier Al plates, it can still be used. Just watch any sharp edges that can chafe on the PEX.
Thanks, Mongo. Great advice, as always!
Is there any chance you could post a pic of one of these?
Miami
Sorry, no pics in my hard drive. I'd thik a web search would show some basic ones. I'm probably way overdue for getting a digital camera...
Hi Mongo hows it going?I'm starting to lean towards the 1/2" pex,the 3/8" pex is a special order(pipe and fittings)the supply houses just don't sell enough to stock it reguarlly.I would have to be very accurate on the pipe and fittings estimate,otherwise another special order and time delay.The 3/8" pex sounds good in thoery.I was told that 3/8" is half the diameter of 1/2" so you would only flush out half the amount of cool water to get to the hot stuff,just wondering was it practical in the real world.
As far as the manifold goes/I made one up of 1" copper in the field(big enough???) with full port ball valves a few feet away from the WH.The cost was about the same as compared with one that was bought.No real savings there,but if I want to add on later its a lot easier. Was wondering what the pro's use
Thanks Greg
3/8ths does indeed have about half the cross-section of half-inch.
A 1" manifold should work fine. Volume-wise, the cross-section of 1" tubing is about the same as a single 3/4" run plus two 1/2" runs running simultaneously.
Those full-port valves are pretty nice, eh?
Those full-port valves are pretty nice, eh?
Yeah they are!Gate valves ,globe valves who needs them ha ha
This home run manifold stuff is way to cool.I only wish I knew about it sooner.I got a bad habit of installing something at the new house ,then finding something better(rip out it, install the new)no wonder its taking me for ever to finish LOL
This pex stuff is pretty cool too.I've been taking some RFH classes at Stadler Viega in Mass.to learn more about it even cooler!
Thanks for the reply!
Stay safe Greg
re - This pex stuff is pretty cool too.I've been taking some RFH classes at Stadler Viega in Mass.to learn more about it even cooler!
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I dug up and read the PEX article that ran in FH.
The Stadler-Viega fitting system seems better/easier then Wirsbo's.
The article also mentions it's a good idea to use the same brand fittings and tubing.
After settling on Wirsbo as the tubing choice after reading all comments, I'm now wondering about the Stadler-Viega tubing, both for heating and domestic water lines.
Hmmm....
I cant really comment on wirsbo(I heard that there very good)The Stadler brand just seems well put together(bronze fittings,stainless steel press fittings).There whole system looks top notch(expensive though)
The classes I"ve been taking are $150 a pop/but they give you a starter crimp tool set that list for $480.So all around that's the brand I will go with.Their instruction booklets are very informative too.
Stay Safe Greg
Thanks for the reply -
If this stuff is anything like other German products such as Viessmann, then I can only assume it will be well thought out.
I'll visit their web-site and look up their training program.
I'm wondering, though, if their crimping tools and fittings will work well on established brands such as Wirsbo ?
Not sure on that one,though I was wondering.Another thing to consider is that some of the manufactures products are not available at all of the supply house's.Some of them only carry one brand.I have to go about 15 miles out to get the Stadler stuff.Kind of a pain if you forget something.
re - I have to go about 15 miles out to get the Stadler stuff.
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I don't think there are any Stadler sources in our area.
Also, it seems Stadler isn't calling their tubing "pex".
They actually compare theirs to PEX as being different technology.
This may mean their fitting system is designed for their tubing specifically.
And finally, they don't publish a searchable data for suppliers of their product.
It's a tightly managed supply chain, as is typcially encountered by other German brands such as Viessmann boilers.
Priced higher at lower volume and perhaps less headache for them.
Wirsbo seems to have taken the mass market approach, making their products easier to obtain.
This probably increases the risk of DIY mistakes ?
I've looked everywhere locally and on-line for the Stradler-Viega sleeve press tool and their black Pexcel (PEX C) tubing with no luck. Can the Stradler-Viega tool and fitting be purchased on-line? Viega bought out Vanguard, Vanguard's Vanex PEX (PEX B) is now called ViegaPEX.
Thanks.