H-31 Fresh Water Lines

Reg M

.
May 21, 2016
131
Hunter 31 Montague
I recently bought a by-pass kit from an RV dealership to install on the hot water tank of my 1984 H-31. The kit as well as the 6 feet of new tubing I bought are 1/2 inch as is the existing fresh water supply line to the hot water heater, however, all the rest of my fresh water system is grey in color and a bit smaller than the new stuff. A friend who has a CS 30 of about the same vintage as my boat tells me he had the same stuff and could not find fittings for it so he replaced the whole thing. I think the old grey stuff has NPT threads because one screws directly onto the hot water exit line from the water heater. Has anyone had any luck adapting the new half inch stuff to the old greay stuff? If I can't adapt it I will have to replace my whole system. Thanks. Reg
 

pateco

.
Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
I think Hunter used the precursor to PEX plumbing, PB pipe.

•PB (polybutylene) - Polybutylene is a flexible plastic pipe that is usually gray, but can also be blue or black, with copper crimped rings securing the pipe at connections. It is usually stamped with the marking “PB2110.”
The piping was used in residential water supply piping from 1978 to 1995, but is no longer manufactured. It was billed as “the pipe of the future” at first, and its low cost and easy installation made it an alternative to traditional copper water piping. PB was especially prevalent in mobile homes manufactured during the 1980s and early 1990s, but we also see it installed in site-built homes of the same era.
Beginning in the 1980s lawsuits, claiming that defective manufacturing and installation had caused hundreds of millions of dollars of water damage from ruptured pipes, began to mount into the thousands. Although the manufacturers never acknowledged that PB pipe is defective, they eventually agreed to fund a class action settlement for just under a billion dollars to resolve homeowner claims. The period for filing a claim ended in 2007.
While the exact cause is uncertain, it is believed that the oxidants (such as chlorine) in public water systems react with the plastic, causing it to flake and become brittle. As the integrity of the piping deteriorates, tiny fractures develop, which can expand over time and cause a sudden failure of the pipe and resulting water damage..
I know I have seen the little white flakes in my sink aerators. You can still get fittings for PB pipe, but If I ever need to make changes, I am going to switch to PEX.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
+1 It's PB, and any repairs, mods etc on Bella will be PEX. I have the crimp tools I used on the house.
 
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Reg M

.
May 21, 2016
131
Hunter 31 Montague
I checked with the local hardward store and they will lend me the crimping tool. I also contacted the RV dealer and their parts guy says they have an adaptor.
 
Dec 22, 2013
14
Hunter 34 Oak Harbor
We just replaced some water lines and fittings in our Hunter as well. I used PEX fittings and tubing from Home Depot, the tubing I used was 1/2 inch as well and the grey tubing was 3/8 so were we could replace the grey lines we used step down fittings. The PEX stuff worked great just push the fitting on and no leaks, we ended up with a way better system and was one of the easier boat projects we've completed!
 

Reg M

.
May 21, 2016
131
Hunter 31 Montague
I picked up the adapter today along with a few other fittings and tackled the job. It took only a couple of hours and the adapter from 3/8 grey tubing to 1/2 inch PEX worked great. Unfortunately I need a coupe more fittings so that is another trip to Charlottetown tomorrow (good excuse for a ride on my Goldwing) and the job will be done. Now in the future I just need to turn the two bypass valves, remove the pickup from the tank and stick it in a gallon container of plumbers antifreeze and turn on each tap in turn. I have a piece of garden hose to connect to the hot water heated drain which will reach the bilge. Another successful project completed!