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Thread: High Filter Pressures??

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    les_garten's Avatar
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    High Filter Pressures??

    I have a Pentair Intelliflow and a Pentair DE Filter.

    I needed to clean the filter because of high pressures. I took the filter apart and a number of grids were holed. So I replaced them all. Put in New DE but my pressures did not go down?

    All the returns are returning strong flows.

    Any ideas about how to go about troubleshooting this?

    I have a Pentair 320 Feeder and a Electric Heat Pump heater.
    14x30 PebbleTec(Caribbean Blue) 12,000 Gals BORAX
    Pentair IntelliFlo <<>> Pentair FNS Plus DE
    Pentair 5G Intellibrite w/Intellibrite Controller
    ROME Solarium 125 Heat Pump
    Kreepy Krauly Classic <<>> Pentair 320 Feeder

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    Mod Squad JohnT's Avatar
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    Re: High Filter Pressures??

    Does your pressure gauge go to zero when you shut the pump off? Does your filter have a multiport valve you can set to recirculate?

    What pressure do you normally run at and what is it now?
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    les_garten's Avatar
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    Re: High Filter Pressures??

    Quote Originally Posted by JohnT View Post
    Does your pressure gauge go to zero when you shut the pump off? Does your filter have a multiport valve you can set to recirculate?

    What pressure do you normally run at and what is it now?
    Yes it goes to zero.

    If I switch to recirculate it is zero and stays at zero.

    It should run around 10-12 PSI aqfter a good clean and it was running 25-30+. So I went to clean and found the grids that had some issues.

    I replaced all the grids and it is exactly the same as before.

    Also the Intelliflow says I need to service soon.

    Thanx for the quick reply!
    14x30 PebbleTec(Caribbean Blue) 12,000 Gals BORAX
    Pentair IntelliFlo <<>> Pentair FNS Plus DE
    Pentair 5G Intellibrite w/Intellibrite Controller
    ROME Solarium 125 Heat Pump
    Kreepy Krauly Classic <<>> Pentair 320 Feeder

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    JasonLion's Avatar
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    Re: High Filter Pressures??

    Are you running the IntelliFlo in one of the constant flow modes? Also, what speed/flow do you have it set to? Finally, did you switch to the IntelliFlo just recently, or has it been working correctly for some time and just started to have problems?

    Any blockages on the return side can cause the pressure to go up. That could be an issue with the filter, but could instead be a valve being closed that should be open.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Richard320's Avatar
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    Re: High Filter Pressures??

    I'd still suspect the gauge. My returns slow down noticeably when it gets time to clean. If your water is circulating well, and you have new grids, it's most likely the gauge, not the filter or plumbing.
    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.
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    les_garten's Avatar
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    Re: High Filter Pressures??

    Quote Originally Posted by JasonLion View Post
    Are you running the IntelliFlo in one of the constant flow modes? Also, what speed/flow do you have it set to? Finally, did you switch to the IntelliFlo just recently, or has it been working correctly for some time and just started to have problems?

    Any blockages on the return side can cause the pressure to go up. That could be an issue with the filter, but could instead be a valve being closed that should be open.
    I have all the valves open presently.

    The Gauge is a Wika Oil filled. The reason I think the gauge is OK is because the Intelliflow says I need to clean as well.

    I have not changed the intelliflow since initial setup. I have it set in manual right now because the pool needed a little cleaning after being off for a few days and I have some DE that got in the pool somehow.

    I normally have it at 60 gpm and do a turnover in like 3-4 hours. 10,000 gallons

    Right now in manual it is running pretty fast.

    I may pull all the Jandy valves and the multiport apart and see if there is some trash in there.

    Reason I think it is not the gauge is because it is a Professional gauge and the Intelliflow is complaining as well.

    - - - Updated - - -

    Quote Originally Posted by Richard320 View Post
    I'd still suspect the gauge. My returns slow down noticeably when it gets time to clean. If your water is circulating well, and you have new grids, it's most likely the gauge, not the filter or plumbing.
    I would think that as well except this is a good gauge and my Intelliflow is complaining as well.

    I have another spider coming for the multi valve. I may have another gauge as well. One of the cheap plastics that come on the valve.
    14x30 PebbleTec(Caribbean Blue) 12,000 Gals BORAX
    Pentair IntelliFlo <<>> Pentair FNS Plus DE
    Pentair 5G Intellibrite w/Intellibrite Controller
    ROME Solarium 125 Heat Pump
    Kreepy Krauly Classic <<>> Pentair 320 Feeder

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    JasonLion's Avatar
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    Re: High Filter Pressures??

    Right now in manual it is running pretty fast.
    The faster you run the IntelliFlo, the higher the filter pressure is expected to be. If it is running faster than it's normal speed then the higher than normal filter pressure is to be expected. What is "normal" for filter pressure totally depends on the speed you are running the IntelliFlo. So if you have been changing the speed the IntelliFlo is set for, it is to be expected that the filter pressure will be different than normal.

    Another thing to keep in mind: if several grids had holes, then the filter pressure would be lower than "normal". Holes allow water through without filtering. Fully intact grids will have more resistance to flow and thus cause higher filter pressures than grids with holes. If you got your impression of what "normal" was when the grids were already damaged, the current behavior is to be expected.

    Finally, the FNS Plus comes in several sizes, all but the largest size are too small for the IntelliFlo to ever be used at full speed. Or to say that another way, it would be normal for an IntelliFlo at full speed to damage the grids of any but the largest model of FNS Plus. Running the IntelliFlo in constant flow mode, will allow it to ramp up to it's highest speed as the filter gets dirty. If used with one of the smaller FNS Plus filters that would be expected to damage the grids unless you have configured the IntelliFlo with a limited maximum speed.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    les_garten's Avatar
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    Re: High Filter Pressures??

    Quote Originally Posted by JasonLion View Post
    The faster you run the IntelliFlo, the higher the filter pressure is expected to be. If it is running faster than it's normal speed then the higher than normal filter pressure is to be expected. What is "normal" for filter pressure totally depends on the speed you are running the IntelliFlo. So if you have been changing the speed the IntelliFlo is set for, it is to be expected that the filter pressure will be different than normal.

    Another thing to keep in mind: if several grids had holes, then the filter pressure would be lower than "normal". Holes allow water through without filtering. Fully intact grids will have more resistance to flow and thus cause higher filter pressures than grids with holes. If you got your impression of what "normal" was when the grids were already damaged, the current behavior is to be expected.

    Finally, the FNS Plus comes in several sizes, all but the largest size are too small for the IntelliFlo to ever be used at full speed. Or to say that another way, it would be normal for an IntelliFlo at full speed to damage the grids of any but the largest model of FNS Plus. Running the IntelliFlo in constant flow mode, will allow it to ramp up to it's highest speed as the filter gets dirty. If used with one of the smaller FNS Plus filters that would be expected to damage the grids unless you have configured the IntelliFlo with a limited maximum speed.
    I'll have to see if I am running it too fast on a few settings.

    - - - Updated - - -

    On another note, could this be resistance from a heater going bad and increasing resistance?
    14x30 PebbleTec(Caribbean Blue) 12,000 Gals BORAX
    Pentair IntelliFlo <<>> Pentair FNS Plus DE
    Pentair 5G Intellibrite w/Intellibrite Controller
    ROME Solarium 125 Heat Pump
    Kreepy Krauly Classic <<>> Pentair 320 Feeder

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    Re: High Filter Pressures??

    From what the OP is saying, I think he has a VF pump not a VS. So any restriction that reduces the flow causes the pump to increase its speed in a effort to maintain the set flow rate. It sounds like there is something restricting the flow somewhere.
    If that is correct: When you switch to recirculate are you bypassing the filter and does that allow the pump to run slower and maintain flow? If so the restriction is in the filter, if not its elsewhere.
    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

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