New connector compatibility with existing water lines

[djousset]

I need to replace a few fresh water fittings and am not sure what I have (gray plastic, semi rigid). Are shark bite connectors compatible with this stuff if I cut off the old fitting? The simplicity of the shark bite connectors is appealing.

[dfelsent]

What is the outside diameter? 1/2”? 15mm? Is the tubing smooth?
I’ve got 15 mm looks like that and use quick connect fittings.

[fourlyons]

That looks like the stuff on my daughter's boat. On her boat it is 1/2" od. I found 3/8" pex tube and fittings to be compatible.

[wholybee]

Direct replacement to what you have can be found here:
https://www.plumbingsupply.com/polyb.html

Those fittings (if they are the ~1/2" OD) size will work with any pipe the same OD as 1/2" copper pipe, including 1/2" copper pipe. Note the ID of the grey pipe is 3/8", and the outside is slightly larger than 1/2" It is sized to have the same OD as copper pipe with 1/2 ID. It's a not normal way to size a pipe, but done for compatibility with other 1/2" pipe.

[GordMay]

Polybutylene [labeled “PB 2110", or “CSA-B 137.8"], is a flexible, usually light grey 'plastic' pipe/tubing [or white, but may also be blue, black, or silver], used in residential plumbing and hot water heating systems, from the mid-70s through the mid-90s.

Several factors have been found to lead to the relatively fast failure of “PB” piping "Quest" plastic fittings and crimps are one [often over-crimped], but the more serious ones are high chlorine water supply, prolonged UV exposure, and prolonged exposure to the high heat of the water, or the surrounding environment.
The major cause of failure is simply that the core molecular structure of the material was not well suited to the requirements of a water supply pipe, so the pipe gets brittle over time, and is accelerated by the above factors.
Once the pipe is sufficiently brittle, it only takes a small movement in the line, through sudden pressure change, being bumped, or even through temperature changes, and the line can split or crack, resulting in potentially major water damage.

This article discusses some options, for fitting replacement:

Tips for Repairing Polybutylene (PB) Plumbing Pipe
➥ https://www.thespruce.com/polybutylene-pipe-2718633

[Capt Clark]

Diane,

My experience with these Quest fittings is that they fail quite often. I’m not sure but the picture looks like a 15 mm fitting. These are easy to replace with any of the newer designs. Your local chandelier should have them. I think it’s now Watts Acqualock or something like that. I like the Sharkbite fittings but I haven’t seen them in metric sizes.

[NorthCoastJoe]

PEX tubing has become very common and cheap. 20+ years ago you had to be a contractor to buy it and take a class on its use and crimping. I have a over $300 crimp tool to prove it.

I would consider replumbing the boat in PEX. For as few fittings as you need in a boat that size Shark-Bite would work well. Shark_Bite is easy to work with and they are removable if you ever need to and reusable. The only special tool you should have would be a tubing cutter so you get square tubing ends. But if you are careful you can do it with a blade.

I have repiped several boats in PEX with no problems.

The only thing PEX needs to be happy is to stay out of the sun.

[GordMay]

For accessible areas, push-fit fittings, often sold under brand names such as SharkBite [1] or John Guest [2], are the easiest way to make a repair.
1 ➥ https://www.sharkbite.com/us/en
2 ➥ https://www.johnguest.com/us/en

For inaccessible repairs, the best option is to use a Watts transition coupling [3] designed specifically to transition from polybutylene to PEX pipe. The PB-to-PEX transition coupling is made of brass, and it compensates for the difference in the inside diameter of PB pipe and PEX. This transition coupling also has two different crimp rings, one that is specifically meant to be used to secure the transition fitting to the PB pipe and one to secure the transition to PEX.
3 ➥ https://www.watts.com/products/plumb...ystems/lfwp17b

[djousset]

Thanks for the input, it prompted some reading about Quest and the lawsuits over product failure. I've been told the fittings are discontinued. As mine fail one by one it might be time to think full re-do rather than piecemeal retro-fit. It's daunting to think about re-plumbing the boat but I’d feel good about a fresh start, and with good measurements I might be able to start a "dry fit” at home in the off season. I was just relishing the idea that I finally had no big projects for spring….Ha!

[Jammer]

The PB to PEX transition fittings mentioned upthread, from Watts and others, are the way to go. You have to crimp them with a crimp tool but they're smaller and more of a sure thing than sharkbites.


The problem with PB was cold flow. The material never really completely solidifies and eventually flows out from under the crimp rings over many years. This is a big deal if you have a house plumbed with PB and expect it to last 50 years. But I would imagine that on a 1980s boat if you replace any leaking fittings, and replace easily accessible runs with PEX, the transition joints will last for the remaining useful life of the boat.