Greetings, Two of the poly butylene tees in our boats freshwater plumbing system failed recently (well one failed, the second failure had an assist from me as I attempted to address the first failure). The two failures bracket the plumbing runs that include the pressure tank. In our boat that plumbing is under the head sink. I remember reading when I last replaced the freshwater pump that the newer pumps do not really require a pressure tank. The plumbing for the pressure tank really complicates the this repair. Has anyone removed their pressure tank and found it to be superfluous? The less I need to mess with that old gray plastic pipe the better off I’ll be. I also had to replace the galley sink faucet this year. Any advice appreciated.
I have had issues with that polybutylene tubing. Also, the fittings and tubing are no longer manufactured. I’m sure you know that. I converted to pex and bought cheapest tools I could find to crimp the bands. I’ll just replace all that outdated tubing and fittings with pex if I encounter future failures. Yes I would not put a pressure tank in the system. The pump is adequate to deliver the water without storing pressure. I used conversion inline fittings from polybutylene to Pex. I’m sure most plumbing supply places sell them because many houses were plumbed with the gray stuff and it failed. That’s why they stopped making it. I found mine on Amazon.
1 Piece XFITTING 1/2" Push Fit x 1/2" PB (polybutylene) Conversion Coupling, Brass (Pack of 2)
Some do, and you may want to look for them. Not all pumps sold today do, so be sure to check the specs for the ones you’re considering.
-- Bob
There is a lot to be desired with the factory plumbing on these boats. I replaced around 125’ of vinyl hose in Sandpiper with around 60’ or 70’ of pex and everything runs perfectly and there is a lot more room under sinks and in lockers.
If you do go pex go with what is called pex A or Aquapex. It uses an expansion tool that you can buy for under $100 to expand the piping which then shrinks back to fit tightly over the inserted fitting.
The advantages are no metal parts, full id through the fittings, ability to rotate tubing on fittings after assembly, and tubing that can be repaired if kinked.
Also while you need to get your crimper into tight places to crimp the rings on pex B, with pex A you can expand the pipe first and then (quickly) get it into the tight place and onto the fitting.
Yup, I removed the expansion tank. The new pump cycles a bit more but that’s of no consequence really.
Regarding the accumulator tank. I’m not a plumbing expert, and I agree many modern pumps don’t mind short cycling.
I’ve been told the accumulator is more valuable in systems like Soave’s that have a hot water tank with a heat exchanger using engine coolant as a heat source. Makes sense to me that as the water in the tank heats up it will expand. I think the accumulator has enough cushion to absorb the expansion so the pressure relief valve won’t spit out water.
Again, not an expert but the presence of a hot water tank might influence the pros/cons. I’ve never looked carefully at Soave’s water system because it just works.
As an aside, I’m conflicted on the value of a hot water tank. Came with the boat.
Sail on,
Rob…
You can get a pump that doesn’t require a tank, but my preference is to use a tank . The pump not constantly cycling means a likely longer life, and I prefer to quiet of infrequent pump noise, especially at night. The tank can be installed remote. I used a conventional 2 gallon expansion tank and can run my tap for over a minute, much longer at modest volume. I used PEX, absolutely worth paying for the tools if you can’t borrow them.
I installed a new Johnson Aqua Jet Varible Flow pump (Model WPS 5.0) in my NS30U this spring and removed the accumulator tank. Everything is working well including the my Isotemp hot water tank. The pump turns on when water is required at any tap but it is very quiet. It does not come on intermittently unless there is a leak in the water system.
Good luck!
Mike Stangl
Mariposa
NS30U / Hull #272
Dutch Harbor, RI
Thanks to all who shared their knowledge and experience on this topic. I ordered a DIY level pex tool set yesterday. Not sure yet what I will do with the accumulator tank but it is very small so my pump cycles nearly every time water is called for at any outlet. I still have an on-demand hot water heater so I’m leaning toward removing the accumulator. Thanks again. This owners forum continues to be an invaluable resource. I wish you all fair winds and following seas.