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PEX plumbing for potable water

Maine Sail

Member III
Well, HomeDepot just got a crimping tool, two rolls of pex, one red and one blue and a bag full of sharkbite fittings back. Much thanks for sharing the lessons learned.

One question though; I'll be replacing 3/4" main to 1/2" branch ID hoses. Have you been able to maintain good pressure at the faucet with 3/8" throughout?

Again, many thanks,

Mort:egrin:

Mort,

A large majority houses in this country are plumbed with 1/2" copper and street pressures are often in excess of 80-90 PSI. Our house is "pressure reduced" to 100PSI and our 1/2" copper lines will peel the skin off your back in the shower while washing a load of laundry, flushing the toilet and watering the lawn all at the same time.. Just took a shower while watering the lawn with my wife doing the dishes all on 1/2" line.

Most boat pumps are set at below 40PSI so 3/8" is more than enough and far easier to plumb. The most flow restriction I have ever seen comes from small micron water filters not from using 3/8" line. 3/4" is way overkill on a boat as is 1/2" but 1/2" is much more reasonable than 3/4". Even if there was some noticeable restriction that is never a bad thing on a boat when dealing with only a fixed amount of water on-board.:nerd:
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
For whatever it's worth, I replaced almost all the original Qest tubing with 3/8 hose, because that's the size the hose came in. Our local industrial hose/fittings supply house has this bright yellow (!) air supply breather hose with fabric reinforcement, rated to 300 psi, and certified FDA approval liner.

Low price per foot. For reformatting all of our fresh water runs it was ideal.
I would caution that there is a drop in pressure when the head sink faucet and galley faucet are on (rarely) at the same time.
Note B: that might also be a sign that our particular pressure pump model is a touch low in its GPH output.

Loren
 

PDX

Member III
The brand of PEX escapes me but what was used on my boat had no clamps, etc. on the fittings. The PEX was literally expanded, stretched to fit over the barbed fitting ends, then it shrinks back and seals on the fitting. Fittings were available in brass or plastic. I liked the system because there were no O-rings, clamps, etc.

Another source for plastic fittings is the John Guest company. Another friend used these on his boat and loved them. Much cheaper than "marine" stuff too.

RT

Wirsbo is the brand that popularized the shape memory system for fitting PEX. They may not be the only player in the game now. Their system requies a specialized tool to expand the PEX and it is not cheap. Very popular system for residential plumbing water system replacements here.
 
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