Hot water Plumbing Material

[Rex Delay]

Hardware store says I should use Pex (?) for the hot water piping system. Considering the difficulty of access to crimp the fittings, how bad of an idea is it to use simple 1/2" plastic tubing for the hot water system, just like the cold?

[Dymaxion]

Clear vinyl stuff will balloon up if water temp and pressure get high enough. At least use the stuff with the woven criss cross fibers in it. Pex pipe is great if you can manage it.

[Rex Delay]

Thank you.

[FlightPlan]

Pex is the right material to use. Generally you can rent the correct tool to assemble the fittings from the plumbing supply house, or just buy the tool and resell it when you are finished with the project. There are pex tube hand expanders that are a lot cheaper, but difficult to use in tight quarters. Crimp materials vary, but they rust. I re-piped my hot and cold water in red and blue Uponor pex tubing and fittings. I purchased the Milwaukee Kit and it includes several sizes of expansion heads for around $400.


It is not recommended to mix fittings and different tubing products. Stick with one or the other systems. The beauty of the system is minimal fittings required if you run your hot water source to a central manifold and from there to your outlets. The drawback is that the tube cannot make sharp turns that would collapse the tube. In a boat that isn't always convenient, and more fittings may be required, thus more joints. But if you make good square pipe cuts, expand the tube correctly and seat the pipe to the fitting all the way home, you will see that in 20 seconds the pipe memory will bite the fitting and you can't pull it apart without heating it and cutting it out.

[sailormed]

On my Hunter all the hot and cold water piping is Pex with push fittings, My water pressure on my jetty here in France is more then double the standard city water pressure. Never had a fitting leek or unseat itself. Fittings are from John Guest or Seatech. Be sure to buy the right size for the tubing. I personally prefer the Seatech fitting as they use metal retainers grips. So no crimping necessary.

[jkleins]

I use the push fittings as well. They work great and you can get spares just about anywhere. In a pinch you can use the sharkbite connectors from the hardware store even on the metric sized pipe although I like to just order the 15 mm size online or get the Whale connectors from the chandlery. Our boat was plumbed like this from the manufacturer 16 years ago and has been pretty leak free.

[sailorboy1]

use the push on connectors, be sure to get a few spares and tubing

save your fingers and buy a plastic tubing cutter at same time instead of trying to use a knife

[a64pilot]

My old boat has the clear reinforced vinyl with hose clamps.
In my opinion, Pex and shark bite fittings are far superior, although my stuff has lasted 30 yrs so far.
You can even allow Pex to freeze and it won’t bust, or course you don’t want to do that, only drawback to Pex that I know of is that UV eats it up pretty quick, so don’t use it for anything above deck.

[Cadence]

Originally Posted by Rex Delay

Hardware store says I should use Pex (?) for the hot water piping system. Considering the difficulty of access to crimp the fittings, how bad of an idea is it to use simple 1/2" plastic tubing for the hot water system, just like the cold?

What type of plastic and what is your definition of tubing?

[HopCar]

When I had my boat built I used clear vinyl with red reinforcing threads in it.
If I was doing it today, I’d use PEX and Seatech fittings. It would be a whole lot easier to install, no tool needed.
35 Series - High Performance Thermal Plastic - Quick Connect Fittings - Manifolds - Valves - Sea Tech, Inc.

[pcmm]

You don't need an expensive tool to crimp the fitings on PEX There are a variety of crimps you can use. I used the stainless crimp rings that have a "bump" in them that the crimper squeezes. I've had good success using a cheap pair of large end nippers from HF to do my crimping. They have a pair of 16 inch end nippers that supply more than enough crimping pressure. The tool cost $14 (without a coupon!). I replumbed my entire 41' boat (forward head, galley, aft head, etc) with 1 roll of red and 1 roll of blue. I think each roll was $20!

[stnick]

When i installed a new hot water heater I used 3/8 pex with push on fittings. I also have
A couple a turn off valve push on just in case of a leak. No leaks in 3 years !
I redid the whole boat new pipes new faucets ,new pumps !
I replaced all the water pipes hot and cold. Pex is easy to push thru , I abandoned the old removed what i could and got the job done ! morgan 38

[wefleenor]

I plumbed my new boat in 2010 with nothing but PEX tubing and push-on fittings. No problems. Just make sure you don't cut corners on the fittings - make sure they a lead-free.

[US1Fountain]

I also replumbed my boat completely with PexA using the Milwaukee expander tool. Granted the tool was a good expense, but during my search, the expander always was the highest recommended method among home plumbing contractors. The Pex A can make fairly sharp bends, 4" radius for the 1/2" tubing if I recall. The push on sure is easy, and slightly faster, but at some point the higher cost of the Sharkbite fittings can help offset the expander tools high cost. My plan was to sell the tool once done to justify the cost, but now that time has past, having the tool for any plumbing alterations later on is a must, so the money spent in the past is a forgotten matter. Im just not trusting of the pushon fittings and the o-rings. Just a minute single leak is not acceptable to me and I felt the expander is the better option.
I dont believe you can mix the Pex type A tubing with Pex B or C if I recall.

[Pete17C]

I work for a HVAC/plumbing contractor, PEX with push on fittings has been in use for years with few problems. It's great for retro-fit work and in tight spaces.

My radiant heat uses PEX tube and old school brass barbed fittings w/hose clamps and I've never had a leak.

Just make sure you cut the ends square and fully engage the tube into the fitting and you're good.