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Adding D.C. Fresh Water Pump

Discussion in 'Ocean Yacht' started by jlresq, Apr 14, 2018.

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  1. jlresq, Apr 14, 2018
    #1
    jlresq

    jlresq New Member

    Joined:
    Oct 25, 2017
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    I have added a D.C. fresh water pump in parallel with my AC pump. I was hoping to leave the D.C. pump on all the time and hook up to dockside water. In theory, the dockside pressure should be greater than the cut in pressure for the D.C. pump so it should not come on when hooked to dockside water. However, yesterday, my D.C. pump was running, my on board water tank had emptied and I can find no sign of the lost water. I have read all prior posts. I have no switch or circuit breaker to activate a check valve in the fresh water system so the spigot on the port side now permits water in from dockside but also out if the fresh water pump is being used. This seems odd. What am I missing and any ideas why my tank emptied while connected to dockside water ---- other than an unknown leak? Thanks.
  2. rpontual, Apr 14, 2018
    #2
    rpontual

    rpontual Member

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    Based on your description the solution you have is similar to the one I had (except that I did not have an AC pump). However I had a checkvalve by the city connector in the interior side of the boat.

    One time I had a problem that caused the loss of fresh water without any vestige of water inside the boat. It turns out that the fault was the checkvalve by the city connector. Somehow the leak occurred outside the boat because the connector was designed to only “seal” under pressure.

    Regardless of the cause of your problem I suggest adding a high pressure checkvalve by the city connector.
  3. chesapeake46, Apr 14, 2018
    #3
    chesapeake46

    chesapeake46 Senior Member

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    Check valves are usually mechanical so there will be no breaker or switch.
  4. Pascal, Apr 14, 2018
    #4
    Pascal

    Pascal Senior Member

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    Was an outside faucet partially open?

    Refill the tank, restart the pump, unhook the water hose and see if water comes out
  5. captainwjm, Apr 14, 2018
    #5
    captainwjm

    captainwjm Senior member

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    First, never leave the dockside water on while away from the boat.
    Second, "the spigot on the port side now permits water in from dockside but also out if the fresh water pump is being used. This seems odd" because it is odd. I've never seen such an arrangement.

    My guess is, assuming that the dockside water was turned off, that the water from the tank emptied out through the hose, as suggested by Pascal's response.
  6. rpontual, Apr 14, 2018
    #6
    rpontual

    rpontual Member

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    Location:
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    If the marine had a back flow stopper or if the connector in your boat has one (like mine), all it takes is for the marina to shutoff the water or of you to close the marina water. As I said above, regardless of the root cause it is desirable to have a high pressure check valve by the city water connector.