Fresh Water Pump Won't Quit

[Scott Berg]

Originally Posted by capn_billl

There have to have been boats sunk that way, most "urban legends" started somehow.

Every year we either rescue or red liar a boat that was sunk by city water... Not a legend at all. We think it's stupid to leave water connected but see it every day.

[peghall]

Definitely not urban legend! Shore water connections left on when no one was aboard sank an average of 10 boats a year on Lake Lanier during the last decade I was there...I personally know of two very near misses--one sailboat owner who woke up in the middle of the night to use the head and stepped out his v-berth into calf deep water...another who only took his dog for a run on a Sunday morning and returned after just an hour to find several inches of water covering his cabin sole. And that's just on one inland lake!

Boat fresh water plumbing isn't designed to withstand "shore water" pressure..Pressure reducers are an integral part of shore water connections...but there are only two types of pressure reducers--those that have failed and those that will...making it absolutely essential that shore water only be connected with someone is aboard and AWAKE to hear the FIRST gushes in the bilge...'cuz the volume is more than 3 big bilge pumps can keep up with.

It's not enough that water on the dock just be turned off when you leave or turn in for the night...the hose should be disconnected from the boat.

The systems that only refill a water tank are a bit safer than those that install downstream of the water pump, but not enough safer to make it worth the risk to leave 'em connected.

[skipmac]

Originally Posted by jwalk

Ok,turned pressure valve screw counterclockwise and pump continued to run with good pressure at all outlets.Other thoughts?

Have you tried isolating the pump intake side to eliminate the possibility of air leaks? A small air leak on the intake side of the pump could give exactly the symptoms you see.

Disconnect the hose from the intake side of the pump and replace with a short hose going directly to a full bucket of water. Turn on the pump and see if the problem goes away. If it does, then somewhere between the water tank and the pump you are sucking in a small amount of air that does not let the pressure switch turn off the pump.

You might also see air or spitting at the faucet when you run the water.

[jwalk]

Afraid I have

[mrm]

Originally Posted by jwalk

Ok,turned pressure valve screw counterclockwise and pump continued to run with good pressure at all outlets.Other thoughts?

Disconnect everything from output side of the pump and block the output shut. Energise pump (temporarily). If it continues to run, pressure sensor is likely defect (has a short).

Another possibility is that pressure sensor is ok, but the pump has an internal 'short' inside (perhaps a broken membrane) so it circulates water internally.

[skipmac]

Originally Posted by jwalk

Afraid I have

Ah shucks.