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"PEX" Water Lines In RV - Has Anyone Replaced Them?

PEX Water lines

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#1 MadHungarian


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Posted 29 January 2014 - 09:22 PM

When I was crawling around in the back of my Coachmen Class C the other day I noticed that the water system in this thing is fitted with the dreaded "PEX" style water lines. Has anybody ever had problems with these lines leaking? Ever replaced them with CPVC?


As a side note, I also noticed that the fresh water holding tank feed line has been cut and capped on both the tank and system sides, which leads me to wonder whether or not the tank has a leak in it. The fresh water fill line had also been disconnected from the tank. Rather scary, as the fill line is awfully close to the AC converter!! I could see a major catastrophe happening had I tried to fill the tank!!  :o

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#2 Erniee


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Posted 30 January 2014 - 07:33 AM

PEX is actually the best - love the stuff.

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Ernie Ekberg
Bluebird Wanderlodge- 43

Weatherford, Tx

#3 Elkhartjim


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Posted 30 January 2014 - 08:17 AM

I agree, Ernie.  Unlike PVC/CPVC, I don't have to worry about the Pex piping freezing and breaking. I only wish I had the manifold system like in my sticks & bricks.


A friend of mine is in the process of re-plumbing his motorhome with PEX after loosing a lot of the PVC due to freeze damage.

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Jim S
2008 38S Fleetwood Bounder DP

Houston, TX area

#4 Born2travel



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Posted 30 January 2014 - 08:27 AM

I have to ask - why is it the "dreaded" PEX.  It is mostly bullet proof and simple to work with. PEX joints and lines are way more forgiving to elements and bouncing down the road than PVC joints and pipes.


You can always use an air compressor to pressurize (at low pressure) the holding tank and see if you have a leak. Spritz it with soapy water and see if you get any bubbles. That way if/when you find a leak you don't have gallons of water draining to a level below the breach.

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#5 kaypsmith


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Posted 30 January 2014 - 11:36 AM

I agree, pex is the best. I plumbed my conversion with it and do not regret it at all. Although, I did use the brass sharkbite or gatorbite fittings, depending on where you buy them for the name. The most important thing to remember is you must make sure the pex is free from any burrs when installing, as they will damage the o-rings and will cause a potential leak.


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1988 MCI 102A3
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#6 huffypuff


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Posted 30 January 2014 - 01:26 PM

I not sure what lines my coach is equipped with but I had a freeze of the basement month-half ago in Twin Falls, ID at 8 F because basement heater failed. The Markings on is 160 psi burst @ 73.4 F 100 psi @ 180 F and is a clear white tint with brass fittings.  It had no damage and was thawed out as we got near Las Vegas, NV.  

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#7 englemanbarry@gmail.com



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Posted 30 January 2014 - 02:40 PM

Pex (cross linked polyethylene) is the best pipe out there without a doubt.  I sold pex for 20 years in Colorado for everything from water lines to snowmelting tube in very expensive homes in the Colorado mountain without any problems.  I think the pipe you are thinking of is Polybutylene which has nothing to do with Pex.  Polybutylene pipe wasn't even that much of a problem but the acetyl fittings were a huge problem nationwide.  Polybutylene does not exist anymore.  Don't rip out your Pex and go to CPVC!!!!

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#8 TerryO



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Posted 31 January 2014 - 12:14 AM

I think the OP has Poly Butalyne and PEX confused. PEX is far better than any other options. I've been in the plumbing trade for 40 years and did a lot of repipes in sticks and bricks back in the 90's as a part of the PB class action lawsuit. The main problem with PB though was the fittings not the tubing.
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