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avarusbrightfyr's avatar
avarusbrightfyr
Explorer
Jan 05, 2020

Fresh Tank Filling on City Water

Hello all,

I'm new to this forum and wanted to start by saying hello and I'm glad to be here!

I've been living in my travel trailer for nearly a year now in a trailer/RV park and haven't really been able to use it for the "recreational" part because I don't have a truck yet. Because of that, I've been on city water exclusively since I've had the trailer. A few days ago, I wanted to make sure everything on the boondocking side of things still worked, so I switched over to the RV side on the water selector and filled the tank and ran water through the pump to test things out. Everything seemed to work fine, so I emptied the tank and switch back over to city water.

However, now my fresh tank is continuing to be slowly filled while city water is selected. The rate of fill is much higher when RV is selected and much lower when on city water, so my assumption is that the selector valve is not sealing properly, but I'd like to get some input from more experienced RVers to make sure I'm not oversimplifying. I've read some things about faulty backflow preventers on the pump causing the fresh tank to fill, so I don't want to discount that just because it hasn't been used much at all.

Any input would be much appreciated!
  • Second_Chance's avatar
    Second_Chance
    Explorer II
    Jan 05, 2020
    Old-Biscuit wrote:
    FILL valve.....if swapped from City To FILL with water supply on the o-rings in the FILL Vlave can get disloadged.....LEAK thru filling fresh water tank

    I haven't used City Water connection since 2008
    Always fill tank and use the pump
    Consistant pressure/flow PLUS if pump short cycles you know you have a leak
    (City water just continues to run until RV is flooded by unknow leak)

    Using the fresh water tank/pump isn't just for boondocking!


    Course with FILL Valve leaking thru the PUMP may continue to RUN because system pressure not high enough to shut pump off
    Water from pump 'round-robin' thru Fill valve---low pressure depending on how bad FILL Valve leaks thru


    It sounds like what Old-Biscuit is saying about the O-rings is what has happened. It's important to turn off the city water and depressurize the system by opening a faucet before turning your water selector valve. Not doing this is a common cause for losing an O-ring. Sounds like you'll need to disassemble the valve and replace one or more O-rings.

    Rob
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Jan 05, 2020
    ScottG wrote:
    The water pump functions as a check valve and it isn't working right.
    Most of the time the problem is the pump has sucked up a piece of junk from the tank (plastic bits form assembly).
    If you're handy, simply take the head of the pump apart and rinse all the parts off (water off of course).
    You probably wont even see the problem but it will work afterwards. If not, you're not out anything.


    Possible ----could be check valve inside the pump (single diaphragm)

    BUT OP didn;t have the problem UNTIL he messed with the FILL Valve
  • ScottG's avatar
    ScottG
    Nomad
    Jan 05, 2020
    The water pump functions as a check valve and it isn't working right.
    Most of the time the problem is the pump has sucked up a piece of junk from the tank (plastic bits form assembly).
    If you're handy, simply take the head of the pump apart and rinse all the parts off (water off of course).
    You probably wont even see the problem but it will work afterwards. If not, you're not out anything.
  • 2oldman's avatar
    2oldman
    Explorer II
    Jan 05, 2020
    Old-Biscuit wrote:
    Using the fresh water tank/pump isn't just for boondocking!
    x2. It's all I use.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Jan 05, 2020
    FILL valve.....if swapped from City To FILL with water supply on the o-rings in the FILL Vlave can get disloadged.....LEAK thru filling fresh water tank

    I haven't used City Water connection since 2008
    Always fill tank and use the pump
    Consistant pressure/flow PLUS if pump short cycles you know you have a leak
    (City water just continues to run until RV is flooded by unknow leak)

    Using the fresh water tank/pump isn't just for boondocking!


    Course with FILL Valve leaking thru the PUMP may continue to RUN because system pressure not high enough to shut pump off
    Water from pump 'round-robin' thru Fill valve---low pressure depending on how bad FILL Valve leaks thru
  • 2oldman's avatar
    2oldman
    Explorer II
    Jan 05, 2020
    avarusbrightfyre wrote:
    I don't use the tank at all for the most part. I didn't want water just sitting in there.
    Ok, but I thought you were testing for boondocking. You'll certainly use it for that. It takes months for the water to get 'disgusting.' I don't think my tank (which is nowhere near sunlight) ever has.
  • All_I_could_aff's avatar
    All_I_could_aff
    Explorer
    Jan 05, 2020
    I agree, no need to keep water in the tank if not using it, but I think the selector valve is not sealing fully. I don’t have any experience with that because my trailer has the old school gravity fill port for the tank
  • avarusbrightfyr's avatar
    avarusbrightfyr
    Explorer
    Jan 05, 2020
    2oldman wrote:
    Don't know why you'd empty the tank.


    I don't use the tank at all for the most part. I didn't want water just sitting in there. I would imagine the water would get disgusting after a while since it's not a sealed system. Bacteria and all that.

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