Forum Discussion

Dave_Chandler's avatar
Dave_Chandler
Explorer
Feb 14, 2016

City water backflow into fresh water tank

I just solved the problem of city water feeding back through my pump and overfilling my fresh water tank. Since its almost new rig, I figured not changing the pump out just because of a little backflow.

I purchased an Aqua-Pro Fresh Water check valve #20818 at Camping World. Also called Backflow Preventer 56574 in their inventory. Cost $6.49.

Then off to Lowe's where I purchased two Brass Hose Barb LFA-390, adapter, 1/2 in ID x 1/2 in FIP. $3.99 each

I cut about 2" out of the line going from my frest water tank to my pump and put this in, with a couple 1/2 to 5/8" clamps, and a little teflon tape. Be sure to look for the arrow on the brass fitting showing the flow direction, you want it pointing toward the pump.

Let me know if this helped anyone out.

  • Fulltimer50's avatar
    Fulltimer50
    Explorer
    Feb 15, 2016
    The valve on the suction line is used to select from where the pump gets its water. If selected up it draws from the tank. If to the clear hose it can draw from an anti freeze container to winterize the system. It can also draw a bleach mix to sanitize the system. In this case if the clear hose is selected the back flowing water will not go into the tank, but outside if the hose is positioned outside so that the water doesnt leak inside the rig.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Feb 15, 2016
    Happy Prospector wrote:
    Hey Dave, is that check valve that you installed, is it spring operated or worked by gravity?


    It is spring loaded......intended use is for RV water heaters

    Typically used in HOT outlet to stop backflow into WH bypassed (winterized).
    Brass nipple with plastic plunger/spring/o-ring (same design as city water inlet and black tank flush connection check valves)
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Feb 15, 2016
    What is the valve on suction line for and why is it pointed away from suction line to pump? (valve is pointed towards clear tubing)


    Check valve in suction line is good for stopping backflow thru pump.
    Shurflo even has a in-line barbed one for that purpose.

    Good job!
    And installing it in suction line is where it needs to be. If in discharge line it will stop backflow also except pump cavity will drain back and pressure switch will make up causing pump to '''burrrp''' occasionally

    Sometimes (especially with new rigs) running pump and using up a tank of water will clear debris holding pump internal check valve open and solve the problem.
  • Happy_Prospecto's avatar
    Happy_Prospecto
    Explorer
    Feb 15, 2016
    Hey Dave, is that check valve that you installed, is it spring operated or worked by gravity?
  • allenm's avatar
    allenm
    Explorer
    Feb 14, 2016
    Thanks for the part numbers. I've been planning on doing the same thing. For now I just close the valve between the tank and the pump. I suspect there is construction debris in the pump's built-in check valve. My TT is less than a year old, and I have always used an outside filter.

    I was glad I had a full tank the other day when our campground lost water for 7 hours after an underground line broke.
  • pcm1959's avatar
    pcm1959
    Explorer
    Feb 14, 2016
    I have heard of this often on several forums. I have had it happen to me twice and both times I contributed it to accidently turning on the water pump while hooked up to city water.
    Upon the next stop no issue. It mostly had to do with a check valve which MAY be faulty. However, I have only ever had it happen when the water pump is turned on. That's a great solution, however. Thanks for sharing.
  • downtheroad's avatar
    downtheroad
    Explorer
    Feb 14, 2016
    Good job...and you will be a much happier RV owner because you have learned a basic fact:

    Do your own repairs and maintenance rather than running back to the dealer every time something isn't just right.

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