REPLACING LEAKING T WATER SYSTEM FITTING

[nashvillekat]

Source of the post Quest is Poly-B. https://www.poly-b.com

Most boats are 15mm plastic tube. It is important not to use Sharkbite on 15mm tube, although it seems to slip on and work well on your boat, Sharkbite it is actually too big therefor the bite/seal is compromised. Sharkbite fittings are designed to work on 1/2" and not 15mm. That being said there are some boats that do have 1/2" tube installed and maybe Carver did at some point. Viper knows best as he has been around so many boats it will make you head spin but I do know my last 3 boats all had 15mm plumbing and this ranges from 1993 to 2007. Point is be sure to know what size you have before purchasing fittings that "seem" to work.

fyi called carver parts 1-800-231-8978 and got return call from PAT.. said my carver 1990 aft cabin model has 1/2 inch pipe.

[Pete]

Source of the post Excellent info, thanks.

FYI

Clearly the 15mm line would be too large to fit into a 1/2" sharkbite fitting in any event.

This is where it gets rather confusing. The 1/2" pex (1/2' is the ID) is actually 5/8' OD which is 15.875mm therefor the 15mm pex used in boats (yes this is OD) will easily fit into a Sharkbite but as I mentioned the seal/bite is compromised. For those who have trouble with metric, the size deference is only .0344 inch.

Someone for god knows what reason decided to identify 1/2" Pex by the inside diameter BUT then decides the metric 15mm style will refer to the outside diameter. Clear as mud right?

15mm OD Pex. https://www.freshwatersystems.com/produ ... mm-od-blue

1/2" ID Pex. https://www.freshwatersystems.com/produ ... ts-id-blue

Just to clarify...I read this post about 3 hours ago when my "blue PEX" 1/2" AND 3/8" Sharkbite fittings did not work for my application.

What started as a drip behind my aft head, I decided to cut the tube and install a shutoff valve until I figured out where the drip was coming from. The 1/2" AND 3/8" Sharkbites did not fit. I ended up taking the tube off of the toilet fill valve and saw the fitting said 15mm. So I ran over to West Marine, they had a small selection of Whale quick connects that fit the 15mm. I replaced the fill valve while I was behind the head and the leak actually was coming from the rubber washer on the flush valve adapter fitting.

In case anyone needs to know, the blue 15mm tubing will not fit on the 1/2" AND 3/8" Sharks. The I.D. of the tubing won't allow it to slip on the 1/2", and the O.D. is too big for the 3/8". Amazon also carries 15mm adapters. Needless to say, I bought a few spares, J.I.C.