shore water connection - backflow?

[MikeP]

I never use the shore water hose connection - preferring to put water in the tank and use it from there. However,

For convenience this morning I decided to hook it up. When I unscrewed the plug in the external water connector there was a lot of water pressure present. It kept draining water until I screwed the plug back in. Recently I had noticed a slight leak from this fitting; tightening the plug stopped it.

I was under the impression that this shouldn't occur but since I have never used it I am not sure. I thought that even with the hose fittings wide open (plug unscrewed) there should not be any water flowing from those fittings when using the boat's water pump. Doesn't the pressure regulator which is installed in the input line to reduce shore pressure contain a anti back flow valve?

[doc g]

If yours is like mine there are two one way bronze flapper valves in the inlet lines one for the stb one for the port if they stick open or are not closing all the way you will get backflow from the water pump pressure into the the dockside inlet line(s).They are located, in my boat, on the port engine room outboard side fwd wall. You should be able to find them . I've heard of people taking them out and using the inlets for deck washdowns using the tank water......Pat

[Dustoff44]

Sounds like the check valve(s) are stuck open. Easy and less expensive replacement is to go back with a shutoff valve where the check valve was. Water pump on / valve open and you have pressurized water at the deck outlet. Water pump off and valve open you connect shore water to pressurize system...

[SeaEric]

Sounds like the check valve(s) are stuck open. Easy and less expensive replacement is to go back with a shutoff valve where the check valve was. Water pump on / valve open and you have pressurized water at the deck outlet. Water pump off and valve open you connect shore water to pressurize system...

Makes sense, except in this scenario would you not need a check valve ahead of the pump to prevent the water backing up through to the tank?

[MikeP]

I know there is a check valve between the pump and water tank and I found the check valve between the external water inputs and the the boat's water system.

So it's clear the external line check valve is stuck open. I'll pull it and take a look and clean/replace it. No rush since it has no effect on the operation of the boat's water system as long as the external screw-in plugs are tight. I'll probably wait until next week when I'm back to being alone :( on the boat.

[DAlter]

Mike,

Same thing happened to me. The check valves get pretty gunked up if they are not used all the time. Also, if possible, you may want to crack open a fitting prior to the water pump and run some water through those lines into a bucket if they haven't been used in a while. There is some scary looking stuff that comes out of the lines and if you haven't installed your filters yet it may give you some ugly looking ice cubes...and I know that dirty ice wouldn't look proper in a glass of Mt. Gay and Coke.

Doug

[SKYCHENEY]

Mine are the same way. I don't worry about it since I have the OEM Hatt push on fittings. Once the fitting is disconnected, no water can come out. It also can double as a fresh water washdown that way.

[MikeP]

Doug - thanks, I found the TWO check valves, one for each external input.

Sky - My external water fittings are just two chrome female water connectors (like a garden hose female end). They look oem so maybe the later boats had the push fittings? (ours is an '80)