Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 10 of 10

Thread: Faulty Multiport Valve? Water back to pool when pump off

  1. Back To Top    #1

    Faulty Multiport Valve? Water back to pool when pump off

    Hayward Superpump through 2" Side-mount multiport valve (MPV) into DE filter.
    With pump primed all is good no leaks noted nor bubbles in pump basket window.
    Upon turning off pump (filter setting on MPV), there's an audible 'gurgle' as the water drains down the vertical clear connection between the pump and the MPV and eventually air gets in the pump filter chamber and back out into the skimmer lines (so it takes a bit to prime again when you turn it back on). All this happens in may 60-90s. There is no check valve between the pump and the pool.
    After lurking around on this site (very helpful) I noticed that after I turn off the pump, there is a vacuum effect from the "waste" port on the MPV. I went ahead and plugged the waste port temporarily with a screw-in style wall return plug and this drastically reduced but not quite eliminate the problem.
    Now when I turn off the pump I can hear a faint 'hiss' of air leaking into the MPV somehow but I can't locate it (is it within? from spyglass? from edges of mpv due to bad seal/gasket?). I'm comfortable taking things apart but don't know where/what step I should do next? I suppose the easy thing first and reseal/seat the spyglass but if that doesn't fix it what should I be doing or looking for?
    Thanks-
    Warren
    Toms River NJ
    Attached Images Attached Images

  2. Back To Top    #2
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Faulty Multiport Valve? Water back to pool when pump off

    Sounds like you need to rebuild the multiport valve. How old is that valve?

    Does the sight glass have a vacuum relief built in? Mine does.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  3. Back To Top    #3

    Re: Faulty Multiport Valve? Water back to pool when pump off

    Quote Originally Posted by Bama Rambler
    Sounds like you need to rebuild the multiport valve. How old is that valve?

    Does the sight glass have a vacuum relief built in? Mine does.
    Unknown how old the MPV is....I've owned the house 4 years...it has to be maybe 7-10yo, possibly older?
    I'd had it apart over the winter mainly b/c I wanted to see how it worked inside and to lubricate any parts and was surprised how 'simple' it seemed inside but there's obviously something failing.
    The sight glass does not have a vacuum relief built in so far as I can tell.
    Attached Images Attached Images

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Faulty Multiport Valve? Water back to pool when pump off

    Did you lube it good when you put it back together?

    I'd probably just rebuild it. It could be leaking at the valve stem seals.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  5. Back To Top    #5
    Smykowski's Avatar
    Join Date
    Sep 2011
    Location
    Gurnee, IL (North Suburban Chi-town)
    Posts
    3,065

    Re: Faulty Multiport Valve? Water back to pool when pump off

    Sounds like a spider valve gasket failure. I second the rebuild suggestion.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

  6. Back To Top    #6
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Faulty Multiport Valve? Water back to pool when pump off

    You can search for Hayward SP710 parts and you'll find the parts you need.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  7. Back To Top    #7

    Re: Faulty Multiport Valve? Water back to pool when pump off

    OK, so I replaced the spider gasket (took out the old one, had the pool store glue in the new one). Everything runs great however when I shut off the pump I can still hear a suction leak sound coming from somewhere in the multiport. I haven't yet put a check valve on the 'waste' opening of the MPV. If the system is off for several hours then eventually I'll have air in my pump filter basket again.
    Tonight, after vacuuming the pool I wanted to empty the pump filter basket. So I turn off the pump and with the MPV still in the 'filter' position I open the lid of the filter basket. Immediately there is a gurgling sound coming from the big DE drum and there is suction pressure that drains out the filter basket and draws air into the MPV/filter. Should I set the MPV to 'recirculate' to take the filter out of the equation when opening the lid of the filter basket or does this indicate some other problem and shouldn't happen?
    Thanks-
    Warren

  8. Back To Top    #8

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: Faulty Multiport Valve? Water back to pool when pump off

    I would locate that air leak in the multiport. Something often helpful is to take a piece of pipe (pvc works well) about 1" in diameter and place it to your ear and then locate the other end at suspect points on the multiport.....sort of like a redneck stethoscope.

    That has worked for me more than once. If you can pinpoint and fix that leak first, you may not have to look any further.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  9. Back To Top    #9
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Faulty Multiport Valve? Water back to pool when pump off

    A screwdriver also works well as a stethoscope. Just be sure to stick the handle end to your ear and not the blade end!
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  10. Back To Top    #10

    Re: Faulty Multiport Valve? Water back to pool when pump off

    Quote Originally Posted by Bama Rambler
    A screwdriver also works well as a stethoscope. Just be sure to stick the handle end to your ear and not the blade end!
    Thanks - you guys are great (speaking as someone from the medical community LOL!)
    On a leak hunt....

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •