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Thread: why no pressure in filter

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    why no pressure in filter

    I am responsible for a 36k pool at an apartment complex. I have no experience but I'm learning. I cleaned my DE filter an now have no pressure in the filter. The guage on the pump body also says 0. When backwashing the filter shows 5psi. I don't want to screw something up but I cant figure out why I have no pressure.
    36k, FNS plus 60 DE filter, in ground cement, 40-60GPM

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    Mod Squad Bama Rambler's Avatar
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    Re: why no pressure in filter

    You didn't close a valve and forget to open it back again did you?
    Is the pump strainer full of water?
    Are you sure the gage isn't defective?

    Oh, and welcome to TFP!
    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

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    Re: why no pressure in filter

    Hi Dave, the only valve I have used is the filter /backwash valve. It's a "t" handle that is so stiff it hurts my hand to operate, pulling up enough to barley rest the peg on that level is hard ,so is twisting it back to center after pushing it down..

    Yes the pump strainer is full, and the pump is pumping as indicated by the 40 to 50 gpm at the flow meter

    I considered a defective gage, but I get a reading of 5 psi when backwashing, so it must be working

    there is another gage on the pump body at the base of the basket area. It stays at 0 psi also

    Do you mind a little background? I started managing these apartments in Oct '10 There was a pool service company coming by once a week. He would be there 5 or 10 mins then leave and I had no experience, so no way to know if he was doing his job. Anyway next month we had a number of rent checks stolen (former manager boyfriend, what a knucklehead) and we took a serious blow to our operating capital. Hence, no more pool service. We just cant hire someone to to fix it or train me, so this site seems to be my best find yet. So I took the filter apart and hosed off the membranes reassembled it and added the required DE. I never looked at the gages until then so I dont know if it was registering before or not, but now it's not. I noticed an "o" ring stuck under the strainer basket in the pump so removed the plate where the motor attaches and bought a kit and reinstalled th new "o" rings (only two, the irregular shaped seal on the plate bolted to the motor and the smaller 3' or so round ring on the cone it obviously belonged. I had drained the filter for this so decided to open it again and discovered it had no,none, zero DE in the filter.All this time the pump has been running 4 or 5 hours a day and the book says NEVER run it without DE more than 2 min. So I put everything back together (no leaks) added more DE through the skimmer and everything seems fine except no pressure

    Thank you for you time.

    Dan and Irene
    36k, FNS plus 60 DE filter, in ground cement, 40-60GPM

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    Re: why no pressure in filter

    Can you post some pictures of pool equipment?

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    Mod Squad Bama Rambler's Avatar
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    Re: why no pressure in filter

    The gauge on the bottom of the pump strainer basket will read zero unless it's a vacuum gauge.

    It is strange that the filter pressure gauge reads zero but if you're getting a good flow don't worry too much about it. I still tend to believe that the gauge is wrong.
    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

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    Richard320's Avatar
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    Re: why no pressure in filter

    Could that valve not be moving all the way back to filter position? Maybe it's got a circulate position, in which case you would have flow, just none through the filter, hence no pressure reading.
    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!

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    Re: why no pressure in filter

    Thanks for the responses. Today, I think I'll drain the filter again and pull that valve. One question: can I drain the filter without loosing DE?

    Thanks Daniel and Irene

    P.S. I just had a thought, When I pull the "t" handle up to backwash, I pull it up just enough to twist and rest the peg on that level, however maybe I need to continue twisting in order to center the peg at the top position. I stop because I'm don't want to break it. Any thoughts?
    36k, FNS plus 60 DE filter, in ground cement, 40-60GPM

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    Mod Squad Bama Rambler's Avatar
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    Re: why no pressure in filter

    On those valves once you've lifted it enough to turn you've gone far enough. The turning is just to rest the stop on the peg so the valve doesn't move back down.

    I would place it in the center but that's just to insure that the vibration from the flowing water doesn't rotate it off the peg.
    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

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    Re: why no pressure in filter

    Good Evening,

    I did not have the time to take the filter/backwash valve apart and this evening Irene vacuumed the pool. She ask me to help her open the pump in order to empty the strainer basket. When I opened the pump, the basket area drained and it started sucking air and I could hear the filter draining. It had not done that before, and I re-primed the pump, opened the air bleeder valve on the filter, and started the pump. All seemed fine except the tank did not fill up quickly, as it had in the past. I held my finger over the valve to feel the air and it had positive pressure but I, waited and waited and it did not sound like it was filling either. AARRGH! What happened? One other possible factor, A pool service guy said to put a ball in sskimer inlet to increase the vacuum, which she did, of course.

    I'm trying to add some images, bu haven't figured it out yet.

    36k, FNS plus 60 DE filter, in ground cement, 40-60GPM

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    Re: why no pressure in filter

    Did you try removing the ball? It could be completely blocking off the suction line.
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

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    Mod Squad Bama Rambler's Avatar
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    Re: why no pressure in filter

    Quote Originally Posted by danandirene
    When I opened the pump, the basket area drained and it started sucking air and I could hear the filter draining
    That sounds like a check valve stuck open. If that's the case then it could be stuck partially open and also restricting the flow to the pump.
    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

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