Pex-A connectors

[djousset]

I am replacing old water lines with Pex-A. No sea water intake, this is all fresh water, cold and hot water to galley and head. My options for connectors are crimp, push-fit, clamp or expansion. The boat sits on the hard Nov-May in New England (winterized of course).

I am leaning towards expansion fittings throughout, sharkbite is easier but perhaps has inherent disadvantages. Thoughts and considerations?

[Opie91]

Pex-A expansion fittings are great as long as you do not need to make any repairs, they are definitely better than the crimp ones.

The Whale version of Pex is pretty good with the much more user friendly push on fittings. They are a little more spendy but you can take them apart many times and a keep some spare tubing on board for repairs.


https://defender.com/en_us/whale-x-h...connect-tubing

[Lepke]

You can buy Whale Pex push-on fittings on Amazon

[Mexican Hat]

Pex expansions are the fitting of choice for professional plumbers. They are easier to install, as long as you plan the sequence of installation out. You don't want to struggle to get the expansion tool into a tight space or at an awkward angle at the end. There's no issue with corrosion or loosening of components and they seem to hold up extremely well.

They are less vulnerable to damage from kinking or bending as well. If they are damaged, just use a heat gun and they'll return to the original shape. They do not make tight radius turns as easily as regular Pex tube but the supports for 90 degree bends help.

You can buy a manual tool and bulk packs of fittings online and put together a comprehensive installation kit for a reasonable amount. If you haven't done them before do a few practice fittings, but it's really very straightforward.

You can only use the specific Pex A expansion fittings and not all the big US hardware stores carry them. FWIW, the outside diameter is different from Pex compression fittings and they will work on regular marine tubing fittings as well. For example, when fitting to an existing system, you may need to start the replacement run at a clamped hose-type fitting. I have succesfully used them that way though do add a hose clamp for peace of mind.

If you do need to repair or replace them its really not hard. Use a heat gun to soften the collar and slit it to remove it. Then heat the end of the tube and it can be pulled off. You can then trim the pipe back and redo it however you need to. If you cut into the fitting itself even the smallest of knife marks is likely to leak.

[GordMay]

Originally Posted by Mexican Hat

Pex expansions are the fitting of choice for professional plumbers...

What MH said, and...
FWIW:
PEX-a Expansion Fittings should be ASTM- F1960 compliant, certified & listed,

ASTM F1960-21: “Standard Specification for Cold Expansion Fittings with PEX Reinforcing Rings for Use with Cross-linked Polyethylene (PEX) and Polyethylene of Raised Temperature (PE-RT) Tubing”
➥ https://store.astm.org/f1960-21.html

“Not All PEX F1960 Expansion Fittings are the Same” ~ by Mechanical Hub
➥ https://mechanical-hub.com/protect-y...-are-the-same/

[ranger58sb]

Originally Posted by djousset

I am replacing old water lines with Pex-A. No sea water intake, this is all fresh water, cold and hot water to galley and head. My options for connectors are crimp, push-fit, clamp or expansion. The boat sits on the hard Nov-May in New England (winterized of course).

I am leaning towards expansion fittings throughout, sharkbite is easier but perhaps has inherent disadvantages. Thoughts and considerations?

I am mid-process in replacing a water heater, so researched various options to connect existing 1/2" ID, 3/4" OD SeaTech SeaFlex/UniFlex boat hose -- not PEX -- to 3/4" male pipe threads on the new unit.

That included consideration of the various push-to-connect fittings from SharkBite, Whale, John Guest, Watts Aqualock, Flair-It, etc... which may or may note have worked with our 3/4" OD hose... and simple stainless ABA/Scandvik worm-drive hose clamps.

Most of the recommendations I got back were for stainless Oetiker Stepless Ear Clamps (i ordered from McMaster-Carr):

https://belmetric.com/clamp-7mm-band.../?sku=CHPE19.8

To be applied with this tool:

https://www.amazon.com/iCrimp-Cinch-...1zcF9hdGY&th=1

And then I used the same type of clamps (larger diameter) to connect the water heater's pressure/temp expansion outlet to 3/4" ID hose for eventual connection to the existing overboard hose...

Most of those recommendations were from folks with the same SeaTech SeaFlex/UniFlex boat hose that we're starting with... but after having made the plumbing connections (and tested yesterday), I too think these are the most secure way to go. I had to re-do one, to correct a slight leak in one of the follow-on pipe thread junctions... and that tool easily cut off the first clamps I had applied on the input hose... so there wasn't any trauma there...

-Chris

[steve77]

I have had great success with the Shark bite connectors. Before leaving the US for Europe I bought a selection of tees, elbows, etc. from Home Depot/Lowes. They have come in very handy when doing plumbing upgrades and modifications. Of course, potable water only.

Cheers!

Steve

[Capt Clark]

“sharkbite is easier but perhaps has inherent disadvantages.”

I’m with Steve77 in that I like Sharkbite connectors; they seemed to be better made. What are the disadvantages?

[Shrew]

Originally Posted by Capt Clark

“sharkbite is easier but perhaps has inherent disadvantages.”

I’m with Steve77 in that I like Sharkbite connectors; they seemed to be better made. What are the disadvantages?

They have a tendency for failure. Much of it is external influences (e.g. freezing, pipe movement, not properly deburred pipes, not properly installed, not properly supported, removal and reinstallation).

A lot of plumbers regard sharkbite the way that electricians don't trust backstabbing outlets and switches. In both cases they make DIY easier with lots of "I've never had a problem" counter-arguments.

[Jammer]

Originally Posted by Capt Clark

“sharkbite is easier but perhaps has inherent disadvantages.”

I’m with Steve77 in that I like Sharkbite connectors; they seemed to be better made. What are the disadvantages?

1) Cost
2) Useful life
3) Reliability
4) Inability to visually inspect a completed termination.

Useful life doesn't matter on boats; sharkbites will outlast the boat. On a house that may stand for 100 years the problem is that the o-rings may fail over time with exposure to chlorinated water and abrasive sediment.

Reliability/inspection go hand in hand. It is possible to under-insert the tubing so that it is not captured at all by the teeth or (especially if combined with an un-square cut) only one or two of the teeth. This may lead to failure later with movement, high pressure, water hammer, etc. It is possible for scratches on the outside of the tubing to cause weeping or leaking that does not show up right away.

[s/v Jedi]

It is my understanding that Upunor invented the expansion fittings and are considered the leading manufacturer.

https://www.uponor.com/en-us/solutio...nor-pex/propex

[djousset]

Some helpful info here, thanks. I was worried about freezing temps with sharkbite, even with winterization, although I like the ability to undo them. It seems that done properly both sharkbite and expansion connections are pretty reliable and have good longevity.

I recently tried expansion fittings on a home reno project; it was easy and felt very secure. I'll plan to use that for the majority of the Pex-A install.

[sailorboy1]

Originally Posted by djousset

I am replacing old water lines with Pex-A. No sea water intake, this is all fresh water, cold and hot water to galley and head. My options for connectors are crimp, push-fit, clamp or expansion. The boat sits on the hard Nov-May in New England (winterized of course).

I am leaning towards expansion fittings throughout, sharkbite is easier but perhaps has inherent disadvantages. Thoughts and considerations?

in my boats 24 years and with 2 of us on the boat full time for 8 years not a single Whale push in fitting ever failed

just saying

[bdgWesternMass]

Originally Posted by s/v Jedi

It is my understanding that Upunor invented the expansion fittings and are considered the leading manufacturer.

https://www.uponor.com/en-us/solutio...nor-pex/propex

I use a very similar system from Zurn that uses the same tools. There is an adaptor for the Milwaukee tool that works with Zurn.

This is definitely a great system and I don't plan on using anything else. I was reluctant to bring it up because of the required tools. I use this on an apartment building and will be using it on my boat. ABYC doesn't seem to have an opinion on this topic.

[PassionOne]

I recently did a system expansion in my on boat using Pex A tubing (for its added flexibility over Pex B) and Pex B brass fittings with stainless steel clamps (for its strength, inspectability and universal availability). The clamps were clamped using the one handed clamp tool ($50 at HD and it have a blue light that confirms you’ve made a good connection) and care was made to make some of the clamps before it was fed into a tight space and to make the final clamps in easy to access spots. I added a spigot for winter draining/blowing out the line at a low spot. I added shut offs for each fixture it is feeding. The tool is small enough to keep aboard and the spare fittings and some tube is easy to stash in case of an emergency. I would suggest keeping spares of everything and brass end plugs in case you need to plug a line and repair later. For the durability of pex, I think this is a very cost effective way to go. Shark bite and push to fit is debated on land, frowned upon in non access spaces like inside walls and in my opinion a bad choice on a craft that is constantly moving and occasionally bashing in waves.