Author Topic: Pex for Webasto/Proheat (Read 7282 times)

Ericbsc · « **on:** November 23, 2009, 07:30:01 AM »

Has anybody used pex for hydronic heat. I used it for everything else. Greatest thing since sliced bread!!! Not one leak with a thousand turns!! Advise? Good bad?

luvrbus · « **Reply #1 on:** November 23, 2009, 07:37:35 AM »

Eric, they use it in homes it is good up to 200 degrees go for it be sure and strap it down in you bus.FWIW use the brass crimp on fitting

good luck

Ericbsc · « **Reply #2 on:** November 23, 2009, 08:12:03 AM »

I used the brass for all. Would you put pipe insulation on it?

TomC · « **Reply #3 on:** November 23, 2009, 08:34:52 AM »

Pex makes special tubing just for heating. Check out their web site. Good Luck, TomC

prevost82 · « **Reply #4 on:** November 23, 2009, 08:56:10 AM »

That's what HydroHot sent me when I bought the self-install kit. High-temp PEX and brass fittings

Nick Badame Refrig/ACC · « **Reply #5 on:** November 23, 2009, 09:46:55 AM »

Hi Eric,

It's just called "Heat Pex" it has an oxygen barrier and is good for temps to 240geg. Not much more money either..

Try and stick with 3/4" or larger. Especially if you build a manifold because the pumps in Proheats and Webasto's are

not as powerful as conventional/home type circulator pumps. They are magneticly coupled together and tend to

give you slipage under a strain.

Good Luck
Nick-

Ray D · « **Reply #6 on:** November 23, 2009, 02:39:25 PM »

I am just getting started with the PEX, haven't seen brass crimps, I have the copper ones. Are these the same or am I missing something, haven't seen brass?

Ray D

luvrbus · « **Reply #7 on:** November 23, 2009, 02:57:39 PM »

Ray, the crimp rings are copper or stainless, aluminum was available for a while but they have been taken off the market because of to many failures.
I use the stainless crimp rings with Watts brass fittings myself

good luck

Don4107 · « **Reply #8 on:** November 23, 2009, 10:05:31 PM »

Saw an interesting version of what I think was Pex on "This Old House". It was three layers. Two plastic with thin aluminum in between. You could bend it and it would hold it's shape. Have not worked with Pex but it looked like it might be easy to work with.

sweeney153 · « **Reply #9 on:** November 24, 2009, 04:37:39 PM »

I used pex for the radiant heat in my house. 20 years so far no problem. Easy to work with.

Ericbsc · « **Reply #10 on:** November 24, 2009, 07:50:03 PM »

Thats what i'll use then. 5 zones including the dash heat. I am going to use the engine coolant system as the expansion tank. I have valves to take the proheat off line if I have a problem. Good bad idea?

Ray D · « **Reply #11 on:** November 24, 2009, 08:34:35 PM »

Do you guys use fittings for every 90 bend? Trying bend 90's with that stuff is like fighting a damned python and you need a boat anchor to hold it in place; well almost.......

Ray D

Kevin Warnock · « **Reply #12 on:** November 24, 2009, 10:38:25 PM »

I am not familiar with this kind of heating in a bus conversion. Do you put it on the floor directly, and then install a new floor over the top? What kind of floor can you put it on? What kind of flooring material can go over it?

How about in the lower wall below the windows? Would that work?

Thanks

scanzel · « **Reply #13 on:** November 25, 2009, 03:37:08 AM »

A friend of mine just did his whole house with the Pex, including all plumbing, radiant in floor heat and even in floor heat in the garage. I would suggest you visit some Pex internet sites and read into radiant floor heating before you install it in a bus. There are many different ways to secure it. NO you do not want to put fittings in the floor and then have it covered. If you should develop a leak all your plywood would become saturated with your antifreeze solution and it would never dry up. Could be a very expensive and labor intensive learning lesson if not done correctly.

belfert · « **Reply #14 on:** November 25, 2009, 04:37:24 AM »

Some kinds of PEX are more flexible than others. The brand I bought for my fresh water plumbing is quite flexible. I used Flex Pex.

John316 · « **Reply #15 on:** November 25, 2009, 05:02:32 AM »

Quote from: Ray D on November 24, 2009, 08:34:35 PM

Do you guys use fittings for every 90 bend? Trying bend 90's with that stuff is like fighting a damned python and you need a boat anchor to hold it in place; well almost.......

Ray D

Yes. Whenever you do a 90, you need to use a fitting. I am not sure what would happen otherwise

. I guess it would be to big of an arc, and look kinda rough with just a bend, and not fitting.

FWIW

God bless,

John

scanzel · « **Reply #16 on:** November 25, 2009, 05:26:34 AM »

Fittings are not to be used in the floor because of possible leaks, this is why they sell coils of 1000' so that the tubing can be one continuous loop. Go to www.pexsupply.com they carry just about everything you could possible need. Fittings should be either in a wall for access if necessary or in accessible areas.

belfert · « **Reply #17 on:** November 25, 2009, 05:31:03 AM »

Quote from: John316 on November 25, 2009, 05:02:32 AM

Yes. Whenever you do a 90, you need to use a fitting. I am not sure what would happen otherwise . I guess it would be to big of an arc, and look kinda rough with just a bend, and not fitting.

There are special metal or plastic bend supports for making a 90 without a fitting. It does take up a bit more space than a fitting, but no leak possibilities.

scanzel · « **Reply #18 on:** November 25, 2009, 05:38:58 AM »

Yes you are correct, they are recommended so the pex doesn't kink when doing a 90 or a 180 in radiant loops.

luvrbus · « **Reply #19 on:** November 25, 2009, 05:43:36 AM »

Guys you are plumbing a bus not a house use the fittings to relieve the stress common pratice in the RV world in the 1 mil +coaches and it has never been a problem why would they sell the fittings strap in down and worry about other things but do it your way

good luck

TexasBorderDude · « **Reply #20 on:** November 25, 2009, 06:44:27 AM »

I need a part number or source for "Heat Pex" I don't find any rated over 180 degrees. Have chcked Vanguard, (now Viega) Pex Supply and researched the net. Nick, What am I missing?

Just Dallas · « **Reply #21 on:** November 25, 2009, 08:16:30 AM »

Removed

TexasBorderDude · « **Reply #22 on:** November 25, 2009, 08:25:29 AM »

Maybe I was unclear, according to the link below the rating is 200 degrees... I'm looking for the 240 degree rating Nick mentioned.

Dallas, please send me that Google link....

http://www.thermapextubing.com/technicalinformation.asp
ThermaPEX® Tubing Ratings

* ThermaPEX® Tubing carries following ratings as issued by Plastic Pipe Institute: 73° F: 160 psi - 180° F: 100 psi - 200° F: 80 psi

Just Dallas · « **Reply #23 on:** November 25, 2009, 09:56:59 AM »

Removed

sweeney153 · « **Reply #24 on:** November 25, 2009, 10:51:11 AM »

I got mine from
Radiantec Company
PO Box 1111
Lyndonville, VT 05851
1-800-451-7593
www.radiantec.com

They have been in business a long time and are very helpful. they will help design your layout or the whole system I just started talking to them about my bus. I have no connection to them other then being a happy customer, but I highly re-comend them. I deal with Don Vance DonV@Radiantec.com

Kevin

TexasBorderDude · « **Reply #25 on:** November 25, 2009, 11:05:46 AM »

Quote from: Now Just Dallas on November 25, 2009, 09:56:59 AM

I just went to http://www.google.com and typed in "Heat Pex"

It came up with this:

http://www.google.com/#hl=en&source=hp&q=heat+pex&aq=f&aqi=g-p1g9&oq=&fp=25d2df88517031cf

661,000 sites found, some of which will have what you want.

Mighty cleaver of you Dallas! I looked at most of the links on the first several pages yesterday. Please let me know when you've found 240 degree pex, 'cause that's the real object of the search!

Just Dallas · « **Reply #26 on:** November 25, 2009, 11:49:04 AM »

Removed

TexasBorderDude · « **Reply #27 on:** November 25, 2009, 12:37:43 PM »

Dallas, yep Google works that way... type in words and it searches. I am skeptical that there is such a product as 240 degree pex and asked Nick for a part number or link to such product. None of the specs I can find exceed 200 degrees and since Nick is the expert I asked him to share his sources. So far you or no one else has come up with it... Google will come up with search results (as will Peanut butter Pex too!)

Why? I'm plumbing a hydronic heating system and want a loop to tie into my engine coolant. 200 degree plus coolant circulating and if there was such a thing as a "Heat Pex" rated at 240 degrees (as was the claim in one of the first posts of this thread) I'd like to use it. Seems to be like the mystical Hong Kong doctor, Dr. Chang, who rebuilds hymens. People talk about it, but nobody's seen it done!

Just Dallas · « **Reply #28 on:** November 25, 2009, 03:15:20 PM »

Removed

TexasBorderDude · « **Reply #29 on:** November 25, 2009, 03:52:39 PM »

Whoa, whoa, whoa! I apologize for any offense and appreciate all help given... I'm just trying to find the 240 degree stuff if there is any such thing.

Slow Rider · « **Reply #30 on:** November 25, 2009, 04:14:16 PM »

200 degrees is the max I am seeing.

What are temperature limitations for PEX?

PEX tubing can be used up to 200° Fahrenheit for heating applications. For plumbing, PEX is limited to 180° F. Temperature limitations are always noted on the print line of the PEX tubing.. PEX systems are tested to and can be used with standard T and P relief valves that operate at 210” F and 150 psi.

taken from : http://www.ppfahome.org/pex/faqpex.html

Frank

busing704 · « **Reply #31 on:** November 25, 2009, 05:14:08 PM »

I am going to start plumbing my webasto. Should it be run in a manifold or a loop (4 heads)

Bill B /bus · « **Reply #32 on:** November 28, 2009, 07:50:11 PM »

A couple of thoughts:
Minimum diameter is 0.75" for webasto
Fittings for PEX tubing are internal fittings and are less than the required 0.75" diameter
Looked into using PEX for a buddy's install and came back to the tried and true method of 3/4" copper for the long runs between heaters and heater hose for the connections.
I use a loop system for four installs I've done. Include a "summer" loop. This circuit involves the Webasto, water heater (if included) and surge tank.
I don't crossconnect the water systems, engine coolant and Webasto, because loss of one means loss of both. With my luck I'd lose an engine hose when the outside temperature was low. Then I'd have no motion and no heat and my bride would not be happy.
Just my $0.02
Bill

belfert · « **Reply #33 on:** November 28, 2009, 08:07:31 PM »

If you like the idea of tieing together the engine heat and Webasto heat, but don't like the risk just use a flat plate heat exchanger. If something breaks on either side the other system will still work.

luvrbus · « **Reply #34 on:** November 29, 2009, 04:32:00 AM »

That is why you build a manifold for the system something happens to 1 zone cut it off and the others keep working.

good luck

Paul · « **Reply #35 on:** November 29, 2009, 06:46:30 AM »

We are installing a Hydro-Hot System in the bus now. Found the unit at a salvage store and ordered the rest as a kit from Vehicle System, now Aqua-hot.

They sent us 5/8” ID x ¾”OD TuffPEX by UPONOR 160PSI 73.4’F / 100PSI 180’F / 80PSI 200’f.

The system is not pressurize, so the only pressure would be from the pump and weight of the water. I do not know what pressure this would be but I think it might be 15 to 25 PSI.

The pumps are very low-pressure pumps this keeps the power demand down.

I have been told the length of the runs is critical to keep the power demand down.

Crimp fittings for PEX tubing are internal fittings and are less than the required 5/8” ID diameter. This makes more power demand and slows the flow. I have not used these fittings.

To make sharp bends in places and in places hard to repairs later I am using ¾”OD copper and long radius sweat ells.

To couple PEX to Copper I use ¾” radiator hose and clamps. Use brass insert in the PEX