REPLACING LEAKING T WATER SYSTEM FITTING

[nashvillekat]

Have 1990 Model Carver.

Isolated leak in my pressurized water system to T fitting... leaking at the joint where the tube is inserted in the fitting.

Have Grey plastic tubing and rubber hose tubing 1/2 inch going into fitting.

Need suggestions on how to repair since the fitting and tubing is out of date.

[Tireless]

I have successfully used a product called Shark Bite on the 1/2 inch plumbing in my Carver. May work for you if you cant get a newer fitting. Have never had a failure in the boat, or my house, for that matter Using this product. I would only use Shark Bite in an area that’s accessible.

Greg

[tomschauer]

I believe you can still get the old grey Quest adapter fittings at Lowes or Homed. Consider changing all the piping to pex, before it becomes an emergency.

[Viper]

Ya what you have is Qest plumbing and the fittings are still available from some distributors so marinas should still be able to get them or you can probably find them on line, pretty sure they're available on Amazon still. You can also use Shark Bite as Greg mentioned or Whale or Seatech fittings, they both have 1/2" fittings. They also have adapters from 1/2" to 15mm adapters if you want to stick a piece of Whale 15mm tube to replace the hose. Whale tubing is very readily available but typically 15mm size. There are quick-connect fittings and adapters of all kinds to mend different systems.

Tom's right in that you should consider replacing the Qest plumbing, there's a reason why they stopped using them in building construction, there were multiple failures. Having said that, converting the existing plumbing is a daunting task and probably very difficult to get at the plumbing in some areas. You can convert sections at a time especially if a repair is required. The good news is that as I mentioned, there are adapters to go from the old to the new stuff.

Source of the post..... Have Grey plastic tubing and rubber hose tubing 1/2 inch going into fitting.....

That's a no no and needs to be fixed, though shalt not clamp a hose onto a tube.

[Midnightsun]

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.

[Tireless]

Due to the response from Midnightsun, I looked into the water line diameters that Carver has used in their boats over the years.

Nashvillekat, it would appear that in 1990, Carver used a 1/2" line, as you stated in your post, manufactured by Sea Tec, so you should be fine using the 1/2 " Sharkbite fittings, in addition to other fittings as outlined by "Viper" in his previous post.

In about 2000+ Carver went to a 15mm diameter line manufactured by the same company until 2010, where they went back to the 1/2" line. They are currently using a Sharkbite style of pressure fittings now according to Brian at Carver. I am aware that Sea Ray has always used a metric sized water lines in their boats as well.

I am glad that Midnightsun brought this up, as I assumed I had 1/2" line in my 2006, and explains why the repair I did in my 1999, 356 was fine using the 1/2" Sharkbite fittings. I would not want to use fittings, or recommend fittings that just "seem" to work. Clearly the 15mm line would be too large to fit into a 1/2" sharkbite fitting in any event.

All the lines in Carvers are marked with the actual line diameter, so be aware of what you have before you replace or go shopping for fittings.

Greg

[Midnightsun]

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

[Viper]

Ya confusing for sure. It goes without saying that you must confirm you have the right size fitting for the size tubing you have. Many have been fooled by the 1/2" and 15mm fittings. I don't use the Sharkbite connectors but know many a boater have. I prefer the Whale and Seatech fittings. The ends of their fittings have the size stamped right on them so always easy to tell what size they are even if you don't have the package. A good marina should always have a selection of quick connect fittings, as well as Qest and Flair-It fittings as there are still a lot of vessels out there with them.

[tomschauer]

I happen to own a carwash. As such, I have found that John Guest fittings work very well and are extremely durable even under extreme commercial use. They do make a 15mm to 1/2 coupling.
Spend the extra $ for real guest fittings, not the knock offs.

[Viper]

Oh no, now you went and opened up a can of worms For the benefit of those that might want to do a search on line, we're talking about two different brands and designs here. So there's no confusion because of the similarity in spelling, there is John GUEST hardware as Tom mentioned, and there is the QEST brand.

The QEST brand is the grey stuff you'll still see in some older vintage boats and RVs which I believe is what the OP is talking about. They are the ones that had reported failures and lawsuits in residential builds gone wrong. Personally I've never run into a problem due strictly to a manufacturing failure that I'm aware of. I've ran into split fittings but likely from over-tightening as they've always been at the hot water tanks or water pumps which up here get disconnected every year for winterizing in the absence of by-pass systems. Under those conditions, any plastic fitting including quick disconnect types will fail in time. For the purposes of an insurance claim though due to a failure, it's probably best to replace what you can and not to give them a way out of a claim.

I'll just put out one other caution; it's usually when you disturb things that they're likely to fail soon after. A little too tight or not tight enough, cross- threading, using the wrong tools, etc. Remember it's plastic so care has to be taken not to over-tighten, and don't squeeze the fittings with something like Channellocks, use a wrench. As for how much do you tighten them, can't say, that's something I go by feel, then test for leaks.