Electric One Way Valve

[JLR]

Pardon the general description of the problem. Working here from memory. I want to be able to leave the breaker on for my 110v fresh water pump even when I am connected to dockside water. The dockside water is at a higher pressure so that the pump will not engage and pump water from my tank. However, when I leave the slip, the pump will engage and supply fresh water from my tank. Right now, there appears to be a pulse sort of effect if I have the breaker on and dockside water connected. The one way valve I have now I guess does not close quickly enough or properly to prevent a slight drop in pressure that then engages the pump (to pump water from my tank) while still connected to dockside water. This is not a cut in/cut out pressure issue as I have adjusted these for maximum performance and the solution, I have been told, is a better one way valve rather than a simple pressure one way valve with a flapper. Has anyone ever heard of this kind of a one way valve? Also, assuming I am correct that this is not an adjustment of cut in cut out pressure, is there any other type of one way valve or other gizmo that would solve this brief pulsing issue? Thanks for the help.

 

[MikeP]

The regulator in the system should prevent that from happening. Our FW water system works exactly as you describe it should work. If shore water is attached, then the pressure in the water system is always higher than the cut-in pressure setting for the pump so the pump never runs when shore is connected.

The only thing that should cause the pump to run in an OEM system with shore water connected is if the pressure regulator is set at too low a pressure or it is clogged/not functioning properly; or, the regulator/input water line/external filter (if you use one) is clogged and shore water volume drops too low to maintain system pressure when the shower or whatever is running.

There is a one-way valve involved but as long as the shore water is connected/turned on, that valve has no "function." Obviously with shore water off or disconnected, it prevents system water from leaving the boat via the shore water connectors.

If the system is non OEM, I have no idea.

(This added later) I realize your system uses a 120VAC pump which is non-OEM but if the rest of the system plumbing is oem (regulator, etc) that should make no difference as far as system operation.

 

[JLR]

Thanks Mike. I am a little confused as well as to why this is happening. I forgot to add that the system is no longer OEM because I had the mechanic add a gate valve that directs dockside water to my fresh water tank as a way to fill the tank. Perhaps in the course of adding the gate valve and several one way valves needed to accomplish this purpose, the integrity of the OEM system has changed. Of course, the pulsing does not take place when filling my tank. Thanks for the help.

 

[tonytrakovich]

I agree with Mike. The shore water regulator should be set higher than the cut in pressure for the pump. If for some reason that doesn't work, ie. You have low dock water pressure, you can probably install a check valve after your pressure tank(s). The pressure tank is not required on dock water. Just a thought.

 

[JLR]

Thanks Tony. I intend to take this up this weekend when I decommission. Although I see many electric solenoid one way valves, I cannot seem to find one that has a pressure setting that is adjustable on it. I could always add an extra pressure switch but then it is getting a little complicated just to obviate the need to remember to turn on the fresh water pump when I leave the slip.

 

[tonytrakovich]

I don't think you need any electric valves. A simple in line spring loaded check valve after the pressure tanks and before the house water distribution will work.

I don't use dock water. I fill my tanks and use the tank water. This keeps the tanks fresh. If the tank water sits too long, it gets stale. Also, you can't sink your boat with water that is already on board!

My system: Tank, check valve, pump, pressure switch (set at 30 cut in 50 cut out), pressure tank w/air diaphragm, house water system. Dockside water: check valve, pressure regulator, house water. Pressure regulator is set at 50psi.

I installed a pressure gauge after pressure tanks to see what system is doing.