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

Thread: Help with identifying the cause of suction side leak

  1. Back To Top    #1

    Help with identifying the cause of suction side leak

    I have a 3-way pentair diverter valve that when rotating the handle to one side, the basket connected to my pump starts filling with air, so I am assuming it is a vacuum leak. I thought it might be a leak in the valve itself, so I bought another valve, pulled out the guts and placed them all in the old valve housing. The problem still exists. So now I'm guessing it is either a crack on one side of the valve housing or the 2" suction pipe that leads to my pool. That suction pipe leads to my pool vac inlet and is about 12" below the water line. When my pool was built, I watched them pour slurry over all of my pipes and there is a concrete slab over 95% of the pipe run so if there is a crack in the pipe, I'm hosed. What is the best way to find out where the leak is? I'm thinking about getting a rubber plug to place in the pool vac inlet, drilling a hole in it, and hooking up an air pressure line to it. Then closing all the valves adjacent to the one I am troubleshooting. I can then fill the pipe with air and look/listen for any leaks. Does that sound reasonable? Any help will be greatly appreciated. Thanks, Kory

  2. Back To Top    #2
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Help with identifying the cause of suction side leak

    If you're not losing water, you can rule out a leak below the water level.

    Your leak could be anywhere, even the simple places like the pump strainer lid. By switching valve positions, you might be increasing suction enough to draw in air. I'd start dribbling water over things with a garden hose or else coat any suspicious areas with shaving cream and see if a) the leak disappears or b) you start drawing foam in.

    Pool School - Suction Side Air Leaks
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  3. Back To Top    #3

    In the Industry

    Join Date
    Jun 2015
    Location
    Wildomar, California
    Posts
    423

    Re: Help with identifying the cause of suction side leak

    Hi Kory. Where does the other side of your 3way suck water from? If your pump is 12 in. below water level, a leak should be obvious. Lastly, did you replace the total guts of the valve, including the valve cover?

    - - - Updated - - -

    Sorry, wrong name, correct topic, LOL

    - - - Updated - - -

    Sorry, I was thinking of some other name. But my comment is the right one for you!

  4. Back To Top    #4

    Re: Help with identifying the cause of suction side leak

    Thank you guys. I should have read that pool school article before I posted. I made a diagram of the affected part of my system and attached it. Richard, you were right on. I didn't realize when I was closing V2-C, it was creating more suction because V2-A is a 2" opening. I replicated the problem by taking V2 out of the equation. I closed V2-A, no leak. I then pulled the stop pins out of V3's handle and began to close V3-B. Sure enough, the more I closed it, the more air was sucked into the system. I swapped the pump basket tops/gaskets with my other pump and tightened the pump basket fitting plug at the bottom and the problem still exists. Tomorrow I'll do some more investigation. I think if I try to close V2-B, and the problem still exists, that would rule out both V2 and V3 as the problem. Thanks again for your help guys. Kory
    Attached Files Attached Files

  5. Back To Top    #5

    Re: Help with identifying the cause of suction side leak

    So...I still have the same vacuum leak. I have ruled out all of the suction side diverter valves by taping a plastic bag around the pipes, isolating each one of them and filling the bags with water. The valve and glued fittings were completely submerged in water. I did the same with the pump basket housing to pipe fitting. No vacuum air leak there either. I also put transparent valve covers on top of each diverter valve one at a time and saw no bubbles passing by. I took the pump basket housing out, completely inspected it, and found no cracks. The pump is a Sta-Rite Max-E-Pro 3hp. I have replaced the basket cover, basket cover o-ring, seal plate o-ring, diffuser o-ring, and both drain plug o-rings. The only seal I haven't replaced is the shaft seal. Is it even possible to have a vacuum leak because of a bad shaft seal? This air leak is killing me.....

  6. Back To Top    #6

    In the Industry

    Join Date
    Jun 2016
    Location
    Tampa
    Posts
    62

    Re: Help with identifying the cause of suction side leak

    I might be a little confused but it sounds to me like you may be choking out the pump... First, when you are doing these test (closing valves), I assume V1-C (spa intake) is completely closed? If that's the case, you would never want to close V2-B ... that would choke the pump out (and it would look like a big air leak inside the pump).

    So start in normal operation (with V1-C - spa intake - completely closed) and all other intakes completely open. That means V2-a,b,c are all open and V3-a,b,c are all open. In that position, I assume everything is working fine? Next, close V2-A so only suction is from main drain and skimmer... is everything still ok? Next, close the skimmer so only the main drain (V3-c) is open... everything still ok. Now open the skimmer and close the main drain... still good? Next, open V2-A (of course, V2-b,c will be open as well) and close V-3b... in that configuration, all suction would be coming from your vac line (V2-a). I assume that is the position that is causing problems? If I'm right, let me know and we can go from there - enough V's and A's and B's for me at the moment

  7. Back To Top    #7

    Re: Help with identifying the cause of suction side leak

    There is no air leak in any normal valve position until I start diverting all suction from the "Pool Vacuum Inlet" V2-A. That is a 2" line. So I just looked at my drawing again and realized that the skimmer is also a 2" line, however when diverting all suction from the skimmer, the problem does not exist. So maybe there is some sort of blockage in the "Pool Vacuum Inlet" causing the issue. Can't believe I didn't think of that...Thanks VikingPoolMan.

  8. Back To Top    #8

    In the Industry

    Join Date
    Jun 2016
    Location
    Tampa
    Posts
    62

    Re: Help with identifying the cause of suction side leak

    Quote Originally Posted by emc2kh View Post
    There is no air leak in any normal valve position until I start diverting all suction from the "Pool Vacuum Inlet" V2-A. That is a 2" line. So I just looked at my drawing again and realized that the skimmer is also a 2" line, however when diverting all suction from the skimmer, the problem does not exist. So maybe there is some sort of blockage in the "Pool Vacuum Inlet" causing the issue. Can't believe I didn't think of that...Thanks VikingPoolMan.
    No problem... it sounds to me like a blockage in the vac line. **You know, most pool vac lines have a safety flap at the end (at the pool)... I assume that is not closed? Good luck.

  9. Back To Top    #9

    Re: Help with identifying the cause of suction side leak

    Update: No blockage in the vacuum inlet pipe. Water flows freely in both directions. I also tested diverting all suction through the skimmer and I do indeed get a small amount of air sucked in to the pump basket. If I turn off the pump, there is an air bubble the size of a 50 cent piece floating at the top of the basket lid. I get the exact same outcome when I divert all suction through the vacuum inlet with the safety flap removed and no pool vacuum hose attached. If I put the vacuum hose on the vacuum inlet (creating lower pressure), the air bubble is much larger and occupies the entire clear part the the basket lid. So is it possible to have a suction side leak caused by an old shaft seal? Also, there are no water leaks anywhere. Even when I abruptly divert suction.

  10. Back To Top    #10

    In the Industry

    Join Date
    Jun 2016
    Location
    Tampa
    Posts
    62

    Re: Help with identifying the cause of suction side leak

    Ok... some air in the pump basket may be normal (ideally, no air is best). That said, if you have a suction side air leak, then my advice is the same for anyone else with a suction side leak... get a water hose and find it. I would set all suction to your skimmer or vac line (maybe set all to vac line and then plug in your vac to exaggerate the air leak). In any case, just set it so you see air in your pump basket. Then take a water hose and start hitting all the areas air leaks may be coming in from (pump lid / male fitting/ joints/ valves, etc)... here's my video on how to do that: How to Fix Air Bubbles In Swimming Pool - YouTube .... if you can't find the air leak anywhere 'above ground,' then it's possibly underground.

Posting Permissions

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