freshwater plumbing

[ageless]

I had several qest fittings that were leaking so I chose to remove what was accessible and replace with schedule 40. It was an undertaking to say the least but 90% is complete. One thing that was inoperable when we purchased BEATs Therapy was the onboard freshwater system, there wasn't even hoses plumbed to/from the pump. I have since corrected that but may have had a little oversight. Once the pump reaches set pressure it shuts off as it should, but seconds later it kicks right back on as the system loses pressure. I have checked all the plumbing from the tank to the pump and find no leaks so my thought is there should be a check valve inline from the tank to the pump eliminating back flow once pressure is met. Are my thoughts correct? Should the valve be as close to the pump as possible?
https://photos.app.goo.gl/bLzK5NjKXssYMDQW7

[ageless]

I won't edit my first thought, but I did what every well versed mechanic does, read the manual
It looks like the valve is after the pump, before the main water line

[racclarkson@gmail.com]

Got an expansion tank?

[MadHatter53]

My check valve stopped the dockside from backfilling the tank etc. and was just after the pumps outlet side.

[steve c]

I had a similar problem last fall. I changed the pump after checking for leaks, verified the pressure
on off settings on the pump and set the pressure on the pressure tank. Last resort was the back flow
valve which was between the tank and the pump. I replaced the back flow valve and the problem
went away. As a side note: I could have rebuilt the valve and could have visually checked for
supply water in the reinforced tubing running from the tank to the pump...another lesson learned

[ageless]

Got an expansion tank?

yes sir, right above the freshwater pump

[Pascal]

Most pumps need a check valve on the input side to prevent pressure from bleeding back to the tank. Usually they’re part of the inlet fitting in the body of the pump.

Can’t quite see what kind of pump you have though. If you don’t have a strainer between the tank and the pump debris can get in and keep the check valve partially open

Mach 5, shallow well and stator (galley make) pumps use check valves. Piston diaphragm usually don’t.

[ageless]

Most pumps need a check valve on the input side to prevent pressure from bleeding back to the tank. Usually they’re part of the inlet fitting in the body of the pump.

Can’t quite see what kind of pump you have though. If you don’t have a strainer between the tank and the pump debris can get in and keep the check valve partially open

Mach 5, shallow well and stator (galley make) pumps use check valves. Piston diaphragm usually don’t.

it is a myers hj110s well pump, there's no check valve between the tank and the pump. If the original pump had the valve built in and my Hatteras manual shows another between the pump outlet and main water inlet line then maybe there should be one before and after the pump?

[Sadey]

Not to hijack this thread but what voltage rated pump are you guys using? Mine is a Craftsman shallow well 110volt. Surveyor suggested a 24volt back up. I know theses are mostly AC boats and I have two gennys but Murphy always rides with me it seems. Thoughts?

[ageless]

Not to hijack this thread but what voltage rated pump are you guys using? Mine is a Craftsman shallow well 110volt. Surveyor suggested a 24volt back up. I know theses are mostly AC boats and I have two gennys but Murphy always rides with me it seems. Thoughts?

mine is 115/230v