Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: Air seems to be getting into my pump

  1. Back To Top    #1

    Join Date
    Apr 2011
    Location
    Houston, TX, USA
    Posts
    101

    Air seems to be getting into my pump

    hi all,

    i was wondering if someone can point me to the right direction here.
    if i run my pump on filter for 2-3 hours, it gradually increases the pressure from 10psi to 20psi to the point that very little water goes into the pool. in looking into this some more, i noticed that my DE filter is indeed clean and the problem is that not too much water is coming into the pump.

    If i stop the pump for a second, put the filter level on WASTE for 5 seconds (5 seconds is enough for water to flow back into the pump and i can see it from the skimmer basket on the pump), and then put the pump back on FILTER i get another 2-3 hours of good water flow.

    My filter grids are sparkling clean (I cleaned them up this weekend, including acid washing), the pool is clear, and backwashing does not help this.

    My only assumption is that something is leaking air into my pumping system, but i dont know where to start. as an aside, if i run the pump on RECIRCULATE, it will run all day at full pressure without any issues.

    any ideas?
    14500 gallon plaster pool (replastered in May 2009) : 32ft.L x 4ft.D x 14ft.W
    Pentair FNS Plus 48 sqft DE filter --> New filter grids as of May 2011. I use DE for them.
    Polaris 280 & Aquabot T-Jet Turbo at 2hrs/week. 20ft by 4ft solar heating panels
    Circupool RJ30 SWG set at 80% output & Pentair SuperFlo 1hp 2speed running 8 hrs/day

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,090

    Re: Air seems to be getting into my pump

    A pressure rise indicates a blockage after the pump. If the problem was an air leak, your pressure would drop.

    It really sounds like a dirty filter, but everything you say says you have taken care of that. Have you opened the filter to verify that the backwash is removing all of the DE?
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

    In the Industry

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

    Re: Air seems to be getting into my pump

    Yeah, michmike, JohnT is on the money. If your filter starts out at normal pressure and then the psi increases and the flow is reduced, something is plugging up that filter. That you can run it constantly on recirculate (bypassing the filter) would seem to confirm that the filter is being plugged up.....usually by unseen algae. What do your test results look like?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4

    Join Date
    Apr 2011
    Location
    Houston, TX, USA
    Posts
    101

    Re: Air seems to be getting into my pump

    My test results look fine. i used to have a bad algae problem 2-3 weeks ago. but i fixed it after agreessive BBB treatments, backwashing 1 or 2 a day, and cleaning my filters this saturday (on saturday i sprayed the filters clean, then put them in a decreasing solution for 4 hours and in a 10:1 water - muriatic acid solution for another 3).

    Are there algae that are not visible or green?

    I did verify that backwash is getting rid of almost all DE.
    Here is one other kink. if something is blocking up the filter, shouldn't that be immediate. If i run the pump on waste for 5 seconds and put it on filter again, we start at 10psi pressure again. it takes a while to go up higher again.

    pool results:
    TA 100
    FC 15 (that's still high because i had algae and brought it to 20)
    CYA 30 (this is low, and i kept it there until i am done with the backwashing and i can add cya back)
    ph 7.4
    CH 205
    14500 gallon plaster pool (replastered in May 2009) : 32ft.L x 4ft.D x 14ft.W
    Pentair FNS Plus 48 sqft DE filter --> New filter grids as of May 2011. I use DE for them.
    Polaris 280 & Aquabot T-Jet Turbo at 2hrs/week. 20ft by 4ft solar heating panels
    Circupool RJ30 SWG set at 80% output & Pentair SuperFlo 1hp 2speed running 8 hrs/day

  5. Back To Top    #5

    Join Date
    Apr 2011
    Location
    Houston, TX, USA
    Posts
    101

    Re: Air seems to be getting into my pump

    if i have unseen algaea what is your recommendation guys?
    thank you by the way!
    14500 gallon plaster pool (replastered in May 2009) : 32ft.L x 4ft.D x 14ft.W
    Pentair FNS Plus 48 sqft DE filter --> New filter grids as of May 2011. I use DE for them.
    Polaris 280 & Aquabot T-Jet Turbo at 2hrs/week. 20ft by 4ft solar heating panels
    Circupool RJ30 SWG set at 80% output & Pentair SuperFlo 1hp 2speed running 8 hrs/day

  6. Back To Top    #6

    In the Industry

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

    Re: Air seems to be getting into my pump

    if something is blocking up the filter, shouldn't that be immediate. If i run the pump on waste for 5 seconds and put it on filter again, we start at 10psi pressure again. it takes a while to go up higher again.
    No, it won't be immediate. Your description seems to indicate something is being filtered out of the water....dead algae, debris, etc. It is possible you can't see it in your water but there seems to be no other explanation for your psi increase and resultant flow loss. That you can clear it by going to waste would seem to indicate that just shutting the pump on and off allows the debris to fall away from the grids for a little while.

    If DE filters have a disadvantage, it is that they catch EVERYTHING so they tend to plug up more quickly. Shocking a pool or clearing a really gummed up pool with a DE filter is a big task and requires a LOT of attention to the filter.

    I can think of no other cause and your symptoms are classic.....your system seems to be doing EXACTLY what it is supposed to be doing.....cleaning junk (even thought you can't see it) from the water.

    I think the course of action is to hold your FC up higher than normal for the next few days and continue to "bump" and backwash that filter. I believe your times in between cleanings will soon get longer and longer.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  7. Back To Top    #7

    Join Date
    Apr 2011
    Location
    Houston, TX, USA
    Posts
    101

    Re: Air seems to be getting into my pump

    thank you! I will keep backwashing and dropping more chlorine to see if this will stop increasing the pressure at some point. I appreciate the help.
    14500 gallon plaster pool (replastered in May 2009) : 32ft.L x 4ft.D x 14ft.W
    Pentair FNS Plus 48 sqft DE filter --> New filter grids as of May 2011. I use DE for them.
    Polaris 280 & Aquabot T-Jet Turbo at 2hrs/week. 20ft by 4ft solar heating panels
    Circupool RJ30 SWG set at 80% output & Pentair SuperFlo 1hp 2speed running 8 hrs/day

Posting Permissions

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