PEXing thoughts

luvrbus · March 11, 2016, 05:05:18 AM

I don't know where you guys live but Pex is failing here in Az in the attics of houses,then it could be from the great water we have in AZ it eats anything.I use it because it is cheap and easy to use with crimp clamps and brass fittings

Dave5Cs · March 11, 2016, 10:40:11 PM

George there is a fitting that will go from Copper pipe to Pex check H-Depot. Sharkbite I think has one also.
Remember when you open those valves if they have been closed for awhile you will mix new coolant with old that has been sitting for a long time or worse if there isn't any in the loop it will fill it and you will be about 7 Gallons short!...
Dave5Cs

Geom · March 12, 2016, 06:07:47 AM

Thanks for the info guys!

Yeah it's a real mess under there

I'm not really worried about the PEX. I've seen it deployed in radiant heating floor installation and those are usually hooked to a boiler installation and many use some form of anti freeze. Interesting about using it for solar heating as well!
As far as pressure and vibration, we have pex for our drinking water plumbing and absolutely love it. It's very tolerant of vibration (I often just bend/move it out of my way to work on stuff) and it's rated to 120psi. It's even taken being frozen more than once. No way copper would do that

. Plus as others have stated, rerunning that now would be a major undertaking.

That pvc has definitely got to go, along with all of those additional pieces.

I'm thinking of using a copper/pex reducer that would go directly into the pex. I really don't want to sweat copper to get this accomplished. The location is really difficult to get to and it's just under the wood sub floor. So I may retain the hose and hose clamp portion, attach a street (via hose and clamp) to pex fitting/reducer, and just get rid of the steel and pvc pieces.
I've seen a couple of votes for sharkbite fittings. I wonder if they'd hold up as well as the pex itself, hmm... Will have to check those out.

For now I think I'll close the valve in the engine compartment. Although the line is already full of fluid, if I'm not passing heated engine coolant through it, it should be ok, till I make the changes.

Don and Cary,

That's a really good idea. And I may give that some more cycles. From what I'm finding on line right now, however, the 12v heaters get terrible reviews and appear to be junk. I may fashion my own 12v heater coil core. I've got some kenthal wire and should be able to rig up a 7-10 amp heater that could ride up next to the existing core.

Steve,

The bus was lowered long before we got it. The bus lowering job looks like it was indeed quite a chore. And it was actually done quite well, from what I can tell. Everything is braced and supported well (I've spent much time with a flashlight walking around the area to make sure it's all holding as it should

). And it makes a huge difference in terms of precieved room in here. It was lowered about 4-5" starting from the back wall of the back bay, forward to the middle steps by the cockpit. It's all braced up on steel beams running down the side. I must admit, I don't really know what all is original and what is add-on. Someday I might see a "normal" 4107/4905 to compare

)

zubzub · March 12, 2016, 07:32:57 AM

fwiw the weird joint may be connecting very old pex to more modern pex. Some of the very early pex type tubing did not work with regular fittings (compression or crimp) I have come across it a few times and had to save old adapters to connect it to more modern pex. Kind I came across was blue with a thin metal wall inside, but there may have been others, huge PITA to connect to.

TomC · March 12, 2016, 07:36:28 AM

I used Qest (gray PVC) on my bus from 1994. I've had one valve fail and one fitting crack. Otherwise it has been trouble free.
Now going to use Pex on the truck-mainly since Qest isn't made anymore. Pex is carried by Home Depot and Loews-so easy repair. Pex is used as plumbing on many houses since it is so easy to work with and is much cheaper than copper. There are very nice premade manifolds for Pex also. Good Luck, TomC

kyle4501 · March 13, 2016, 07:26:38 AM

I would use a shark bite type fitting as temporary emergency repair only if the proper fitting is unavailable.
For permanent connection, use a proper crimp ring or quality ferrule & nut fitting. It is more work up front, but less chance of water leaks. Every water leak I have had was a sneaky one that wet more than I thought possible - took way more effort to repair the collateral damage than would have been required to use a better fitting the first time.

Best of luck with your project!

Geom · March 13, 2016, 08:00:41 AM

I found this document online a while back. It is a nice list of different chemicals and PEX's tolerance of them at different pressures and temps. I'm posting it here in case someone finds it handy. This primarily applies to this specific vendor's "PEX" but I believe it's likely applicable to all PEX in general (at least current generation).

https://www.mrpexsystems.com/pdf/technical_documents/MrPEX_Chemical%20Resistance%20Chart.pdf

luvrbus · March 13, 2016, 09:19:45 AM

We have a Coachmen the wife purchased new in 1985 that has the grey poly pipe that stuff has never been a problem,I still see it new RV's of today.Pex needs better fitting the brass one are so thin some water like here in AZ eats the fitting up and the cheaper plastic fitting break you have to deal with problems on about anything you use IMO except the Stainless.Pex is cheap and easy to use but I would recommend buying sticks I redone a rental and Pex in roll is a bitch to work with I spent most of my time trying to uncoil the stuff the sticks worked so much better for me. lol I still have the coils I tied one end to the bus the other to my tractor and stretched it this July heat in AZ all was good I thought the next morning that stuff had coiled back to the original shape that is when I bought the sticks

Scott & Heather · March 13, 2016, 07:41:33 PM

You're cracking me up. Wife is wondering what's wrong with me. I completely understand the coiled pex drama haha! Same here. Stuff stays curved a long time lol

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Dave5Cs · March 13, 2016, 08:52:07 PM

I used the shark bite white pipe and Pex fittings and rings. Work well and no problems in 5 years. I had the grey PB and it would leak at the fittings. So replaced with the white pipe as the would go.
Dave

lvmci · March 14, 2016, 08:27:37 AM

hi All, one of the best things I did with installation of my pex was eliminate 3/4s of the fittings, by using the newer corner slip on 90 degree bend external corner fittings, for every corner, less cuts, fittings and 2 less clamps, lvmci...

luvrbus · March 14, 2016, 09:20:04 AM

Tom, are you talking about the wall sweeps that nail to the studs

lvmci · March 14, 2016, 02:13:47 PM

hi Clifford, these are 90degree corner bends, made out of steel or plastic, available at HD next to pex stuff, they fit over the pex, and then you snap in the other side making a 90 degree turn, as opposed to cutting the pex, inserting a elbow and clamping both sides, the pex tubing stays whole and still makes the corner, reducing the number of chances for a leak. I hope you and Sonja are well, tom...

Scott & Heather · March 14, 2016, 08:59:02 PM

These?

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Geom · March 14, 2016, 09:09:48 PM

Those things are great and significantly reduce cuts/splices, assuming your're not turning a tight 90 degrees. They have quite a long bend radius to them. I'd also recommend the plastic ones over the metal. The metal ones seem to corrode/rust as the pipes condensate due to differing air and water temps/humidity (at least mine have).