Modern RVs, made in the last 10 to 15 years, are plumbed using PEX tubing, sometime called PEX pipe, for the fresh water system. In fact, most new homes and commercial buildings use it too. It is so much cheaper than metal pipe and because it is flexible it is easier and less expensive to install as well.
There are many colors of PEX tubing but Red, for hot water and Blue for cold water are often used.
Frugal RV manufactures may use white or non-colored PEX tubing for both hot and cold lines. The manufacturer of our RV made this choice.
Manufactures can choose plastic or metal fittings to join lengths of PEX and connect the PEX tubing to appliances and fixtures. Regardless of which kind of fittings used, the fittings are connected using a crimp ring that is set with a special crimping tool. These tools are priced starting around $50 and go up.
What crimping tool you need depends on the type/brand of crimp rings being used. After the ring is crimped, a gauge should be used if determine of the crimp is within specs.
Luckily, for the RVer who wants to do his own repairs, it doesn’t have to be that complicated or expensive. There are two common fitting types that do not require expensive tools. While special tools for these fittings are available and can make the job easier they are not expensive. You may find you don’t even need them.
The only special tool that I have purchased is a PEX cutter for around $15. You can use a good sharp knife but the cutter makes it a whole lot easier to get a nice straight cut. Especially in tight spaces. The fact the cutter can also cut smaller sizes of PVC pipe and rubber hose makes it a worthwhile investment to my mind. My advice would be to spend enough to get a cutter made of metal.
I found my PEX cutter at Lowes but here is one that is similar at Amazon.com Eastman 95117 Pex And Plastic Pipe Cutter
Types and Brands of PEX Fittings
The first fitting system I’ll cover is likely the most common one you’ll find at RV parts stores. The fittings are made by a company called Flair-It.
Their advantage is a relative low price and ready availability.
Their biggest disadvantage is the need to push the end of the PEX tubing over a flair on the fitting. It takes some strength and can be difficult to do in a tight space where you can’t get enough leverage. A wrench and a pair of slip-joint pliers are all you need to tighten the compression nuts. Flair-It makes a special wrench that may be needed in a tight space where pliers would be difficult to use. But, so far, I’ve not needed one. The wrench costs under $10.
The second most common repair fitting is the quick-connect or push-on type. Common brand names are SharkBite and Sea Tech but there are others.
The big advantage is ease of use. You literally just push the ends of the PEX tube into the fitting with next-to-no pressure and you’re done! Honestly, I can hardly believe these fittings work. But they do.
The disadvantage is the higher cost of the fittings. But you may decide to the extra cost is worth the convenience. I think I have.
You can buy a special tool called Removal Disconnect Tool for under $5 that makes it easier to depress the release ring. But with a little effort you can depress it with your fingers or pliers..
There is another style of quick connect fitting that is a hybrid of the two types above. The brand name is Apollo Lockfit. I discovered them when I bought a couple of them at Lowes when I wasn’t paying attention. They have the same easy insertion as the standard quick-connects but have a compression nut like the Flair-It fittings. But these compression nuts can be finger tightened. No wrench or pliers needed.
There are fittings and adaptors for every plumbing need. Below are just a few that you may want to have on hand.
The fittings pictured above are only a sampling if the fittings you may want to have on hand. For example you may want to keep one or two 90 degree couplers and one or two ‘T” couplers. An inspection of your RV will give you a good idea of what spare fittings you may need to have.
Remember if you ever need to replace a section of PEX tubing you will need two couplers And don’t forget you’ll need a length of new tubing. I keep about 3 feet in my parts box.
I hope you have a better understanding of how PEX plumbing and fittings work and have enough confidence to do your own repairs if necessary.
As always, if you have questions, suggestions or comments please use the comment box.