Pressure Water Plumbing - PEX, etc.

[Christian Van H]

Originally Posted by seapup

Which of the manifolds (say 8 cold and 4 hot outlets) would be best in a marine install if you want to stay with the expander fittings throughout?

That really depends, Pup. I dont have ANY manifolds on the pressure side of the system, simply Tee fittings. One branches off to the galley for each hot and cold, and one branches off to the head for sink and tub. There's no need to run separate lines from a manifold to both the head sink and the shower, when you can simply tee off from one line. On the other hand, I have a manifold BEFORE the pressure pump, where our three water tanks feed the pump, each with a shut off valve to control water usage. This is a good idea, as a leak or someone who doesnt know any better can drain your entire water supply VERY quickly should all three tanks be available at once. Hope this helps, Chris

[seapup]

I'm stoked about the ProPEX (expander connections) system. I don't see a manifold system that has those connections on inlets though..all crimp, or O-ring? I wnat to plumb with 1/2" and have an 8 outlet cold and 4 outlet hot manifold under the deck plates. Any help?

[TAREUA]

Usually with Uponor/Wirsbo the manifolds or multi-port tees are 3/4" on the inlet and then 1/2" on the ports. Part number say Q2247550, Q2287550, etc will I hope get you in the right area. There are flow thru and dead end models depending on your design.

[Christian Van H]

See here for manifolds: ProPEX Style Manifolds - ProPEX Copper Manifolds - Plastic Valveless Manifolds - Aquacenter Valved Manifolds - PEX Manifolds Some types need to have fittings sweated on to the inlet to complete the manifold...

[captain58sailin]

Great Post! This is my next project after the fuel system.

[Mule]

Speaking of fuel systems, is there a pex system for fuel?

[seapup]

Thanks everyone for the good leads!

[GordMay]

Originally Posted by Mule

Speaking of fuel systems, is there a pex system for fuel?

No ~ but there are products called "Fuel & Oil Hose"; which are available from manufacturers, such as:
Gates
MPI/Marine Products International
Racor, Division Parker Hannifin
Shields Rubber (Sierra International)
Trident Marine Products
Ultra Marine Products
etc...

SAE Standard “J30" Fuel and Oil Hoses:
Covers fuel & oil hose, coupled & uncoupled, for use with gasoline, oil, diesel fuel, lubrication oil, or the vapor present in either the fuel system or in the crankcase of internal combustion engines in mobile, stationary, & marine applications.
Section 3 covers Coupled and Uncoupled Synthetic Rubber Tube and Cover (SAE 30R2). Section 4 covers Lightweight Braided Reinforced Lacquer, Cement, or Rubber Covered Hose (SAE 30R3).
Section 5 covers Wire Inserted Synthetic Rubber Tube and Cover (SAE 30R5).
Section 6 covers Low-Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover (SAE 30R6), (SAE 30R7), (SAE 30R8).
Section 7 covers Fuel Injection Hose Medium-Pressure Coupled and Uncoupled Synthetic Rubber Tube and Cover (SAE 30R9).
Section 8 covers In-Tank, Low-Pressure, Uncoupled Fuel Hoses (SAE 30R10). Section 9 covers Unified Method for Fuel Hose Permeation.
Section 10 covers Low Permeation Fuel Fill and Vent Hose (SAE 30R11). Section 11 covers Low Permeation Fuel Feed and Return Hose (SAE 30R12).es (SAE 30R10).
Sections 10 and 11 cover hose intended to meet low fuel permeation requirements.
Sections 7 and 11 cover hose intended to meet the demands of fuel injection systems.

[P. Gaspard]

I'm an old boatbuilder with a systems engineering background. I have used plastic in marine water systems applications for many years beginning with the Qest, CPVC and Polybutylene products of the early 80’s. Aboard my own 40' Catamaran I took a little different path than has generally been suggested here. I prefer Flair-It 'Plus' fittings to others out there for the following reasons:
1. Fittings are FRP and nearly indestructible.
2. The only tool needed to do the job is a knife to cut the PEX tubing.
3. Flair-It fittings have few parts, and are completely reusable without tools.
4. The fittings operate on the same mechanical principal as compression rigging terminals, but without the sacrificial 'cone'.
5. My own pressure testing of various fittings showed the Flair-It always survived overpressure (to over 300psi!) with the cold PEX tube itself always blowing out well before the fitting. Many other fittings are non-reinforced Acetyl or Nylon, and a few did fail my abusive testing.
6. A common PEX fitting adapter port can have as many as 5 separate parts (JACO, Watts, etc.) a Flair-It has only 2 – body and collar.
7. Using 1/2", in my humble opinion . . just offers crew the opportunity to waste water. My system utilizes 3/8" delivery tube to each service, independently valved, with 1/4" Teflon/stainless o-ringed service hoses from the valve to each tap or appliance. The exception is my Walter Systems demand hot-water heater that is 3/8" X 3/8". Nobody ever complains about pressure or volume, and the spray head at the galley sink still fires spray far enough from the companionway to hose down an unsuspecting crew sitting anywhere in the 9' X 12' cockpit.
7. PEX, like most plastics, is not a good heat sink so insulation of the hot side is really a bit overkill unless you sail out of Alaska. Nonetheless, I did insulate much of my system a year after installation. I could not detect any temperature difference at the taps, and there was no measurable energy savings as a result . . . but then I’m down in sunny Southern California where keeping the popsicles frozen is more of an issue.
8. The Flair-It ¼-turn plastic valves at each service are light, non-restrictive, non-corroding, and allow for immediate shut-off of a single service without affecting the balance of the system.

The Flair-It and Flair-It 'Plus' fittings are interchangeable, and can be differentiated by color: Flair-It standard fittings are off-white, Flair-It 'Plus' are black.

And both are cheap . . . cheap, cheap, cheap.

By the way, I'm not a Flair-It rep, just a cheap sailor trying to build the best for the least - time and money, and trying to anticipate how to make my life simpler down the road - or more accurately, on a dark, sleepless night without tools in hand, halfway between here and nowhere. My boat’s installation is about 6-7 years old and has always been under pressure either dockside or underway, without a single leak.

I hope this adds something new to the already great body of responses in this thread.

Best To All,
Phil
Balboa Island, Ca.

[GordMay]

Originally Posted by P. Gaspard

... I prefer Flair-It 'Plus' fittings to others out there for the following reasons ...
Phil

Greetings and welcome aboard Phil.

Thanks for adding something new & informative to the already great body of responses in this thread.

I anticipate that you’re going to be a decided asset to this Forum.

[P. Gaspard]

Thanks Gord,
I thought of an additional issue that can arise when installing a PEX system. Hopefully this helps someone doing the deed –
PEX, like many plastic products will shrink and grow a surprising amount in reaction to temperature changes. Exceptions would be the fluorocarbon plastics like PTFE or Delrin. In many shape applications this is not noticeable or particularly important. For instance you could observe and measure a 12” square block of plastic as it reacted to temperature change, and while you would see a change, it would not be a remarkable change, and if the end product of this raw material substantially retained this original configuration, then the changes would be of little to no concern – for example turning the mass of plastic into a large doorstop, bowling ball, or paper weight. On the other hand, if you were to extrude that plastic block into a long narrow strip or better still, a long tube, you might be rather surprised how much the tube’s length changes as a result of swings in temperature. Here’s a real-world example: Two of my cabinhouse windows are ¼” thick acrylic plastic. The windows are a little over 9’ long, and taper from a height of about 14” down to maybe 8” over their length. These windows grow/shrink about ¼” in length depending on ambient temperature – cool winter evenings vs. warm summer days. In this application then, you can see where it is important to accommodate this movement in the installation scheme, otherwise its leak city, baby. The rule of thumb is simple; When maximizing plastic’s surface area over length, you will have size/shape changes to consider, especially when the plastic must interact with another material having more stable shape properties. With PEX – particularly the hot side, this means you should always leave a bit of slack especially on long runs. Another example: When one finds that a bend in the PEX must be a smaller radius than a sweep to make a corner, the intuitive solution is to install a hard 90 deg. adapter. But one might also be tempted to anchor the run tight at that corner. This could cause problems down the road by introducing stresses between the relatively stable, anchored fitting and substrate, and the changing tube length as the run cools or warms. The trick to a relatively stress-free assembly is to support the water-laden tubing somewhere near the fitting, in a way that it can still move a bit over its length, and also allow the fitting/tubing some room at the hard structure’s corner to move - and never over-anchor the system as one might with electrical bundles or other types of runs. FYI, this condition in combination with pressure change, not pressure change alone, has been found to be the reason why some PEX installations in homes suffered failures inside walls with disastrous results. One can appreciate attempts to overkill the joining of tube to fittings with crimp-rings and other schemes then, for applications like residential construction where installers likely will not fully understand the physics involved, or exercise the care necessary to insure a trouble-free system. In short, “Idiot-proofing” for the masses has proven necessary.
Phil

[GordMay]

Originally Posted by P. Gaspard

I thought of an additional issue that can arise when installing a PEX system. Hopefully this helps someone doing the deed –
PEX, like many plastic products will shrink and grow a surprising amount in reaction to temperature changes.
... The rule of thumb is simple; When maximizing plastic’s surface area over length, you will have size/shape changes to consider, especially when the plastic must interact with another material having more stable shape properties. With PEX – particularly the hot side, this means you should always leave a bit of slack especially on long runs. Another example: When one finds that a bend in the PEX must be a smaller radius than a sweep to make a corner, the intuitive solution is to install a hard 90 deg. adapter. But one might also be tempted to anchor the run tight at that corner. This could cause problems down the road by introducing stresses between the relatively stable, anchored fitting and substrate, and the changing tube length as the run cools or warms. The trick to a relatively stress-free assembly is to support the water-laden tubing somewhere near the fitting, in a way that it can still move a bit over its length, and also allow the fitting/tubing some room at the hard structure’s corner to move - and never over-anchor the system as one might with electrical bundles or other types of runs.
Phil

PEX should installed loosely, or snaked from side-to-side to allow for expansion and contraction. When strapping, make sure that tubing is free to move in all directions after attachment. There are “special” expansion clips for this pupose.

[boden36]

We went the low tech way - garden hose and irrigation fittingss. Still going strong after 20 years! Regards, Richard.

[P. Gaspard]

Originally Posted by boden36

We went the low tech way - garden hose and irrigation fittingss. Still going strong after 20 years! Regards, Richard.

Kn’oath!

Clever, independent, resourceful, and thoroughly entertaining . . . there’s a reason why Aussies I met on the water over 30 years ago are life-long friends today.
My dad, a proud old US Marine Sgt. Major once said of the Aussies detached to his guerilla training program during the Pacific campaign of WWII; “Those scrappy bastards did the most with the least of any men in the war . . . we were ^!*damn fortunate to have them by our side”

Please forgive my off-topic . . must be the 4th of July weekend talking
:-))))

Phil

[motion30]

My system is copper and I now have a leak I would like to replump with flex hose and clamps What is the proper hose to use ? I do not wish to use pex or any plastic pipe