Replumb with PEX

My boat has reached a point in time when the grey colored water lines are falling apart. After doing research I find the only logical replacement to be PEX.



Has anyone else replumbed their boat using PEX?
Your experiences are important as I look at this project.

Me and Boo said:

My boat has reached a point in time when the grey colored water lines are falling apart. After doing research I find the only logical replacement to be PEX.



Has anyone else replumbed their boat using PEX?
Your experiences are important as I look at this project.

Click to expand...

I did that 2 years ago, I expect it to survive myself.
Used blue pipe for cold water, red for hot. Used manifolds to be able to isolate any line.
Very easy to do if you plan it properly.

L

Like Lou, I replumbed with Pex about four years ago. Very happy with the result. You will need to decide what type of fittings you want to use. I chose the Uponor system that expands the tubing ends and fittings are then inserted. The 'memory' of the tubing contracts over the fitting creating a very strong connection. Crimps and 'Sharkbite' fittings are also popular. There is a lot of pex information online and many video clips showing how to do it.

I just used the white stuff and Sharkbite connectors. No leaks!

I'm all in favor of PEX, and my last couple of boats were built with it right from the factory.


The only suggestion I would have is to check the temp rating of the tubing and fittings. Typical domestic hot water is only 120-130F, and maybe up to 140F. But if you have hot water heated by your engine while underway, it will reach engine temp of 180-190F which is much hotter than typical. I have seen some of the quick connect fittings only rated to 150F, and know of people who have had failures with them.

I can't comment on fittings as they have changed in the past 15 years since I did a few PEX upgrades. My idea here is to use what you feel comfortable installing and repairing. PEX doesn't like tight bends so plan for some 90 degree fittings. Chafe can be a problem so support is well. Don't make long runs over about four feet with straight tight runs. Give them gentle curves along the pipe length. This allows for expansion and contractions and prevents connections from being strained or pulled apart. If you have to go straight, put in an expansion/contraction loop.







Also consider curve braces. I forgot what these are called right off.

twistedtree said:

I'm all in favor of PEX, and my last couple of boats were built with it right from the factory.


The only suggestion I would have is to check the temp rating of the tubing and fittings. Typical domestic hot water is only 120-130F, and maybe up to 140F. But if you have hot water heated by your engine while underway, it will reach engine temp of 180-190F which is much hotter than typical. I have seen some of the quick connect fittings only rated to 150F, and know of people who have had failures with them.

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Rated up to 200F, however also with a max pressure of 80 psi
View attachment pex.pdf

I’m a big fan of Sea Tech fittings. They are very easy to use. You just cut the tube to length and shove it into the fitting. No special tool needed and they are easy to disassemble also. The fittings are reusable if you need to make changes.

Ken E. said:

Like Lou, I replumbed with Pex about four years ago. Very happy with the result. You will need to decide what type of fittings you want to use. I chose the Uponor system that expands the tubing ends and fittings are then inserted. The 'memory' of the tubing contracts over the fitting creating a very strong connection. Crimps and 'Sharkbite' fittings are also popular. There is a lot of pex information online and many video clips showing how to do it.

Click to expand...

While not a boat I just did an entire house and in floor heating system with the Uponor method. One advantage is the the fittings are slightly larger for better flow. In actual use it probably does not matter although, the plastic expansion rings will never rust or corrode.

Rob

twistedtree said:

I'm all in favor of PEX, and my last couple of boats were built with it right from the factory.


The only suggestion I would have is to check the temp rating of the tubing and fittings. Typical domestic hot water is only 120-130F, and maybe up to 140F. But if you have hot water heated by your engine while underway, it will reach engine temp of 180-190F which is much hotter than typical. I have seen some of the quick connect fittings only rated to 150F, and know of people who have had failures with them.

Click to expand...

Good advice. I’m considering PEX as well and hoping the mixing valve on our Isotemp hot water heater will help here. I’m using engine hose from the engine to the hot water tank and PEX to distribute the hot/cold mixed water throughout the boat, so the system (other than the tank) should never see 180 degrees.

I replumbed a previous boat with Sea Tek system. It was great, easy to use if you make square cuts. I also used some benders for turns instead of 90s. Used blue for cold and red for hot. One key issue is it comes in a box rolled up. It doesn’t like to straighten out so sticking it into a cabinet and getting it out the other side can be challenging. I found out you can order it in 10’ straight sticks so the rolled up trying to get it straightened out isn’t an issue.

Never did a boat, but did a house. Great stuff. Sharkbites push-one wouldn't be my move, except an impossible to reach place. They are far more expensive that clamps and normal fittings. The crimper practically pays for itself.

I started with copper crimp rings and finished with the pinch type clamps. I had to get a different crimper, but they were easierbto crimp in tight spaces and I liked them better.

Good advice about supporting it, being careful of really tight bends, and using the occasional bend support to keep it neat. Not sure expansion loops will be needed on looser boat-length runs.

Love it with shark bite style fittings. Replumbed my galley sink last winter as I made the sink twice the original size. All the previous pex plumbing had to move. Figured it would be a pain. Hit up my spare parts bin, couple cuts later and in less than 30 minutes everything was moved, no trip to the hardware store.

One winter my galley froze, one of the sink fittings popped out. After the thaw I just pushed it back in, good as new.

I plumbed my water lines for a new washer/dryer. I used blue for cold, red for hot. I also used shark bite connectors. Yes they are a bit expensive, but well worth it. All at Lowes.

Oh and if they freeze, they don't break...

So what make of push-on fitting will transition from 1/2-inch O.D. copper tubing?

Shark bite makes a 1/2" to 1/2" fitting that can accept copper or pex tube. Other brands make a similar push fitting.
Alternatively, you can sweat a copper fitting onto the copper that is designed for a pex line with crimp.

I just replaced my 30 year old copper flare fittings with PEX. It was a pain but is so much easier to winterize and perform work on it. They don't leak. Have to get the right tools.

ghost said:

One winter my galley froze, one of the sink fittings popped out. After the thaw I just pushed it back in, good as new.

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Has anyone here every tried installing a small air valve so you could blow out the water lines when winterizing?

If you have a mixing valve at your hot water tank, then the downstream piping won't get so hot, assuming the mixing valve works correctly...I think there is a really good argument that any boat with engine heated water should have a mixing valve as a safety device.



Just looking at spec sheets, I would use the SeaTech series 35 or 45, but not the series 10 or 25, just given the temp rating.


Whale quick connect fittings are rated only to 150F, and these are the ones I have see (indirectly) fail.


SharkBite brass fittings look good with a 200F rating.


Sharkbite ProLock fittings are rated to 180F which is cutting it close.


So whatever system you plan to use, just take a few minutes to check the temp/pressure ratings.

makobuilders said:

Has anyone here every tried installing a small air valve so you could blow out the water lines when winterizing?

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Yes. I usually just make up a fitting that connects an air hose to a hose spigot, and pressurize with air via the spigot. I've done this on numerous boats and houses with 100% success, at least so far.


On our new boat build I'm bringing all the outside water lines to separate manifolds (hot and cold) so they can be centrally shut off without shutting down the interior water, and the manifolds have air hose fittings so they can be blown out. It's easy to do when building, but probably impractical on an existing boat.

I prefer copper tubing with flair fittings .Available world wide for repair or modifications.

The problem I have with pex is houses usually use city , not well water so have chlorine in the water.
The water in most houses doesn't sit for weeks or months in a vented tank, so the chlorine stays useful.

Plain old copper does not grow green stuff on its pipes .

Make sure that all PEX tubing is covered/protected from UV light since that deteriorates it quickly, and the last thing you want is a brittle pipe with water under pressure.

PEX-A can be reheated if you kink it to remove the kink, but PEX-B can't, so you have to splice the area where the kink occurred or replace the section.

How about John Guest fittings?

FF said:

I prefer copper tubing with flair fittings .Available world wide for repair or modifications.

The problem I have with pex is houses usually use city , not well water so have chlorine in the water.
The water in most houses doesn't sit for weeks or months in a vented tank, so the chlorine stays useful.

Plain old copper does not grow green stuff on its pipes .

Click to expand...

I use copper where my freshwater runs along the bilge and up to the waterline. Then I chose pex up into the cabin and running to the sinks. So I get the best of both worlds.

Actually, the copper froze and expanded and burst. I just cut the copper off at the waterline where it stays warmer and connected a shark bite to the copper and replace everything above.

Now, where is that seasonal message about nothing freezing in Seattle.

makobuilders said:

Has anyone here every tried installing a small air valve so you could blow out the water lines when winterizing?

Click to expand...

Yes, like TT, I use compressed air to blow out the pipes for winter. I installed air fittings on the water lines and it's very quick and easy. I used to pump potable antifreeze through the lines but air is easier.

If you are going for permanently attached fittings (as opposed to quick connect type) an advantage of the Uponor PEX A type is that it is often much easier to use the expansion tool than an external crimper in confined spaces, like you have on a boat.

I clinched/pinch clamped (as suggested by Rick B.) using the following tool...


Not one leak ever on first try and this one handed tool made it easy to do fitting way back...out of reach with 2 hands.


The second link is to Aqua-pex ...I think I used it because of it's flexibility.....though I forget now.


https://www.homedepot.com/p/Apollo-...aXDDpYcFcaIzXxYvcIBoClTkQAvD_BwE&gclsrc=aw.ds


https://www.supplyhouse.com/Wirsbo-Uponor-F1040500-1-2-AQUAPEX-100-ft-coil-2173000-p

When I installed the PEX tubing I created a manifold with an isolation shutoff valve and drain plug and also a small valve that I can use as both air valve and antifreeze from my 5 gallon bucket. It literally took me 15 minutes to connect the bucket, fill it with antifreeze, turn on the pump and walk around to all my sinks and deck wash-down, and disconnect everything. Winterizing just became a thing to do no longer a chore.

If your using crimps I would also get the crimp remover tool. Makes life that much simpler if you mess up. Home depot has a few kinds.

One other point not mentioned is diameter of PEX to use.
Many marine supply places carry 14mm tube & fittings where the building supply places carry 1/2 inch.
They are close but not interchangeable so you need to decide and plan accordingly.