As an individual who actually used to rep, over a number of years, two different lines of PEX tubing (actually three but that was just brand name badging by US Brass the parrent company). I also sold two lines of commercial/industrial & residential hydronic & high pressure steam boilers, control systems, HVAC
systems, valves and many other products sold to the plumbing
wholesalers all I can say is you guys are WAY, WAY, WAY over thinking it.
I was selling radiant tube hydronic heating systems well before most anyone had even heard of it and well before PEX had even one approval for domestic water use in the US.
The vapor barrier for hydronic systems is to prevent air from being sucked throught the walls of the pipe and into the sealed system as the water cools from 180-200f down to a stand by temperatures. As water is heated it expands as it cools it shrinks. This shrinking can cause air to permeate a non-vapor barrier tube and induce air which leads to corosion. This was a big problem with low mass steel
boilers as air & steel
don't mix well. even with cast iron boilers the air caused problems with rust and scaling.
The bottom line is this. Yes, Wirsbo/Uponor (still think the name change was dumb
) makes a great fitting as does Rehau and both are very good companies. Wirsbo, along with Rehau, were the early pioneers in the US for PEX and both got a lot of arrows in thier backs being pioneers.
The reality today is that ALL the systems work and work quite well when properly installed. All the fittings have been well vetted and throughy tested. The Sharkbite style has been perhaps the most tested and vetted product of them all simply because of disbelievers like many on this forum.
Even Watts, one of the most respected companies in the P&H industry, now has PEX quick connect fittings in both brass and plastic. I can assure you that Watts, of all companies in that industry, would not release a product with their name on it without it being able to live up to the Watts reputation.
I used to sell both Rehau and what is now called Zurn Pex (actually Quest too but we won't go there). All these fittings are strong when properly installed. The Rehau fittings are now even certified to be burried in Gyp-Crete, which they were not when I sold them. The key word here is PROPERLY. We used to run two & three day training seminars for the trade
and still we'd find bad fittings, by properly trained licensed plumbers/HVAC technicians, in floor splices, A HUGE NO, NO back then, and many other issues that would lead to potential failure.
Having personally supervised the instalation of well over 100,000 feet of PEX tubing, we used to sell millions of feet per year, I would advise anyone considering the use of PEX crimpers on a boat to think twice. There are places where it will simply be impossible to make a good crimp or to get the expanders into, even hand expanders. The Wirsbo or Rehau expander is a slightly better option than rings but again there will be situations where you simply can not get the expander into.
Shark bites, Watts Quick Connects or any of the other o-ring types are very, very reliable (I never even sold them and I am saying this).
The worry about your fresh water supply being supported by only an o-ring is WAY over blown IMHO. Hell your entire boat is probably floating on crappy & cheap
junk Ideal perforated hose clamps. I mean really, how many here actually use T-Band or AWAB hose clamps on thier sea cocks??? I'd bet not all that many.. Hell, I'd worry more about the T&P valve and the operating temp of your marine engine
than I would about anything else of you don't want to lose water. For safety's sake it's good practice to always turn off your 12v pump when not using it anyway.
How many of you guys have a fresh water diaphragm/accumulator tank like a Jabsco
or a 12V fresh water pump? Both of these also utilize o-rings. Your engine
is loaded with o-rings & rubber seals
. Your fuel
supply is protected by an o-ring too. Racor fuel
filters and many on engine filters.. o-rings.. Faucets.. o-rings/seals... How many have a PSS Shaft Seal
? Again, the stainless collar uses... you gussed it.. o-rings... LPG cylinder valve.. o-ring...
Wirsbo/Uponor, Rehau, Zurn and many others make great products. Rehau & Wirsbo are by far the most experienced and have the longest history
though US Brass/Zurn, at last check, was the biggest and largest volume seller in the US..
So what does someone who does actually own the tools, who has trained the trade
, spent 12+ years selling and designing hydronic radiant systems in the very early days of it, and who is familiar with most all these companies products use on their own boat?
I'm actually using the Cash Acme Shark Bites..... Let's not forget that they are rated for 200 F and 200 PSI. The water system on my boat barely pushes 40 PSI. Sure I cold have used my Rhaupex expanders and the brass fittings but it's overkill and I just could not physically get those expanders where I needed them in certain locations. Also with the quick connects I can take the fitting apart and re-plumb or make changes without wrecking a length of tubing by cutting the ftting off and having it wind
up 2" to short. I personally think the quick conects are the ideal fittings for the tight quarters we experience on boats. Crimp band conections can be screwed up fairly easily but the expanded fittings are less apt to be screwed up.
For anyone considering this job on a boat I highly recommend 3/8" PEX vs. 1/2" as it is MUCH easier to work with, both for snaking and bending..