Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 16 of 16

Thread: Filter not; pressure low; flow good; what next?

  1. Back To Top    #1

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Filter not; pressure low; flow good; what next?

    I'm trying to solve a problem involving our Hayward 60sf DE filter: it recently stopped filtering.

    The pressure gauge reads low, like it does after backwashing but before charging with fresh filter media. The pump isn't making unusual sounds (nor the filter), and the flow "looks" good despite lack of filtration. By "looks", I mean the surface disturbance and the circulation of floating objects all look like the pool does right after backwashing. I would normally perceive a gradual slowdown and increase in pressure as the filter approaches needing its next backwash. Over many days and an increasingly murky pool, the pressure has gone up a little, but nowhere close to where I normally do a backwash, and nowhere near as fast as normal under these water conditions. I see no bubbles anywhere (e.g., if there were air leaks).

    I already replaced the grids (which were due) and later the manifold (which has failed before, causing mostly similar symptoms). Neither made any difference.

    What else goes wrong with these things that would produce this kind of trouble?

  2. Back To Top    #2
    pwrstrk's Avatar
    Join Date
    Aug 2012
    Location
    Elverson Pa.
    Posts
    4,758

    Filter not; pressure low; flow good; what next?

    Would you say the water is cloudy ? Could be water chemistry issues.
    Could you post a full set of test results and what test kit you are using.
    Also if you could add your location, all pool and equipment info to your sig that will help us better help you. 😎
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

  3. Back To Top    #3

    Join Date
    Oct 2013
    Location
    Chapin, SC
    Posts
    1,141

    Re: Filter not; pressure low; flow good; what next?

    Could be a faulty gauge, does it go to zero when turned off?
    Pool size: 24000gal inground Vinyl-Taylor k-2006 and k-1766 test kits and-speed stir
    Intermatic P1353ME digital timer w/freeze sensor
    CircuPool Si-45 SWCG System
    Polaris 280 vacuum/Polaris PB4-60 boost pump
    Pentair IntelliFlo VS 3hp Pump--Pentair sand filter

  4. Back To Top    #4

    TFP Guide

    chiefwej's Avatar
    Join Date
    Jun 2011
    Location
    Tucson
    Posts
    2,853

    Re: Filter not; pressure low; flow good; what next?

    Do you have a push/pull or a multi port valve? The valve may be leaking water bypassing the filter.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

  5. Back To Top    #5

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by chiefwej View Post
    Do you have a push/pull or a multi port valve? The valve may be leaking water bypassing the filter.
    Interesting; that is something I did not check (other than it always being in the right position). It is a multi-port Hayward valve. How might I evaluate this possibility?

  6. Back To Top    #6

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by pwrstrk View Post
    Would you say the water is cloudy ? Could be water chemistry issues.
    Could you post a full set of test results and what test kit you are using.
    Also if you could add your location, all pool and equipment info to your sig that will help us better help you. 😎
    The water is (or shall I say has become) cloudy. I could scarcely imagine otherwise if there is no filter working.

    Will work on that signature.
    35-ish kgal irregular-shaped in-ground.
    Hayward 60sf DE filter using cellulose media.

  7. Back To Top    #7

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by timerguy View Post
    Could be a faulty gauge, does it go to zero when turned off?
    It does go to zero, and the reading is at least roughly consistent with what I've learned to expect for the amount of flow I described.
    35-ish kgal irregular-shaped in-ground.
    Hayward 60sf DE filter using cellulose media.

  8. Back To Top    #8
    pwrstrk's Avatar
    Join Date
    Aug 2012
    Location
    Elverson Pa.
    Posts
    4,758

    Filter not; pressure low; flow good; what next?

    Quote Originally Posted by our_hummel_abode View Post
    The water is (or shall I say has become) cloudy. I could scarcely imagine otherwise if there is no filter working.

    Will work on that signature.
    Lots of times water clarity issues are a water chemistry problem. Not a filter problem.
    If you could post a full set of test results and what test kit your are using we could see if the problem lies there or not.
    How are you chlorinating your pool ? 😎
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

  9. Back To Top    #9

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by pwrstrk View Post
    Lots of times water clarity issues are a water chemistry problem. Not a filter problem.
    If you could post a full set of test results and what test kit your are using we could see if the problem lies there or not.
    How are you chlorinating your pool ? ��
    Well, first let me ask: Is it even possible to keep the chemistry in line if there is effectively no filtration?

    The symptoms I described are almost the same as a what I observed a few years ago when the filter's manifold blew a hole, except then there was extra noise from the filter. It cost me much less to un-swamp the pool than I would have been spending (to any possible avail?) on bleach and other chemistry during the time without a working filter. From that experience, I also know the current pressure/flow situation is not consistent with water being filtered effectively through the grids. So, I probably should seek some evidence of a working filtration system before spending money on trying to continue maintaining the pool's chemistry.

    I can see how a valve problem could fit all of the evidence when taken together. Is there a good way to evaluate this possibility?
    35-ish kgal irregular-shaped in-ground.
    Hayward 60sf DE filter using cellulose media.

  10. Back To Top    #10
    pwrstrk's Avatar
    Join Date
    Aug 2012
    Location
    Elverson Pa.
    Posts
    4,758

    Re: Filter not; pressure low; flow good; what next?

    You stated you did have some pressure increase so that would suggest that some of the water is going thru the filter. Correct ?
    I'm not sure how to diagnose a valve problem. Hopefully somebody will chime in.
    The last time this happened did you have an algae outbreak during the filter problem ? I would think if the FC level is kept in range for the CYA level, with a non working filter you would still stay algae free.
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

  11. Back To Top    #11
    Smykowski's Avatar
    Join Date
    Sep 2011
    Location
    Gurnee, IL (North Suburban Chi-town)
    Posts
    3,065

    Re: Filter not; pressure low; flow good; what next?

    Low pressure with decent flow could be a suction side issue. More likely is an air leak, less likely is a blockage, but both could be possible. Have you ruled either of those out?
    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

  12. Back To Top    #12

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by Smykowski View Post
    Low pressure with decent flow could be a suction side issue. More likely is an air leak, less likely is a blockage, but both could be possible. Have you ruled either of those out?
    I was ruling out an air leak on the basis of there being no bubbles anywhere.

    Although I'm less confident about there being no blockage (since I never studied hydraulics), it looks like the amount of water moving in/out/around the pool is as much as ever. Not the same as what I see when the grids or a basket are getting blocked up.

    Any other triage steps to consider?
    35-ish kgal irregular-shaped in-ground.
    Hayward 60sf DE filter using cellulose media.

  13. Back To Top    #13

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by pwrstrk View Post
    You stated you did have some pressure increase so that would suggest that some of the water is going thru the filter. Correct ?
    I'm not sure how to diagnose a valve problem. Hopefully somebody will chime in.
    The last time this happened did you have an algae outbreak during the filter problem ? I would think if the FC level is kept in range for the CYA level, with a non working filter you would still stay algae free.
    The slight pressure increase has been over the course of days, and not even close to the amount when I'd decide to backwash.

    When the manifold broke, as with this time, I found myself having to add increasing amounts of bleach, producing nothing better than a murky blue pool instead of a murky green one, and burning through way more bleach than normal. Maybe it had/has something to do with the cellulose (i.e., given a way to circulate into the pool). I dunno.

    When I fixed the manifold, the pressure and flow started behaving as expected. The pressure rose quickly over the span of hours, rather than little over a span of days, and I had to backwash several times a day until the water cleared enough to see the bottom. I then brought the chemistry back in line with TFP guidelines and everything was fine.
    35-ish kgal irregular-shaped in-ground.
    Hayward 60sf DE filter using cellulose media.

  14. Back To Top    #14
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Filter not; pressure low; flow good; what next?

    As was stated previously I believe, a pool going green is usually first and foremost a chemistry problem (insufficient chlorine). The filter is then needed to pull all the dead algae out of the water.

    Sure does not sound like you ever completed the ShockLevelAndMAINTAIN Process.

    FYI, I went for 2 weeks in the middle of the AZ summer without a pump running at all ... and I did not develop any algae or cloudiness by maintaining the chlorine levels. The pool was dirty of course, but the water was clear and algae free.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  15. Back To Top    #15

    Join Date
    Jul 2010
    Location
    Scottsdale, AZ
    Posts
    13

    Re: Filter not; pressure low; flow good; what next?

    Quote Originally Posted by jblizzle View Post
    As was stated previously I believe, a pool going green is usually first and foremost a chemistry problem (insufficient chlorine). The filter is then needed to pull all the dead algae out of the water.

    Sure does not sound like you ever completed the ShockLevelAndMAINTAIN Process.

    FYI, I went for 2 weeks in the middle of the AZ summer without a pump running at all ... and I did not develop any algae or cloudiness by maintaining the chlorine levels. The pool was dirty of course, but the water was clear and algae free.
    The "going green" is a red herring here, first because the pressure problems were apparent while it was blue, and second because I consciously let the maintenance slip because of increasing chlorine costs (quantity et al.) and my not wanting to be wasteful. My asking in the "Pumping Station" was deliberate and well considered.

    And, BTW, I have used the SLAM approach in the past (combined with liberal backwashings) and will be doing so as appropriate to clear up the green.

    As it happens [url=http://www.troublefreepool.com/members/21752-chiefwej]chiefwej wins the troubleshooting prize and a big thank-you, because I replaced the valve assembly (SPX0740BA) and the filter pressure is back to behaving normally for the first time since the situation began. I've been too busy backwashing to figure out yet why replacing the valve fixed it (any suggestions what to check? A cursory inspection didn't reveal any broken plastic as far as I could see), but I can say that the new valve turns so much easier, I thought maybe it wouldn't work. It does work well, and I had just been used to the original valve being very difficult and at the end, extremely difficult to turn.
    35-ish kgal irregular-shaped in-ground.
    Hayward 60sf DE filter using cellulose media.

  16. Back To Top    #16

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,077

    Re: Filter not; pressure low; flow good; what next?

    Richard320 always says, the last thing you fixed is the first thing to check".

    What was wrong with your manifold the last time? How long ago was that? How did you fix it?

    What is your current clean pressure and what is the pressure where you typically backwash.

    I agree that your problem seems mechanical rather than a pool chemistry issue.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

Posting Permissions

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