Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 9 of 9

Thread: Pool pressure shows 0 psi on pump "low speed"

  1. Back To Top    #1

    Join Date
    Jul 2014
    Location
    Cleveland, OH
    Posts
    9

    Pool pressure shows 0 psi on pump "low speed"

    Hello,

    I just realized today that the pool pump (that came with my new house) is a two speed (just turn the switch the other way). However, when I turned the switch to the low speed I get 0 psi on the filter (normally 14 psi on high speed). This is a 75 sqft cartridge system, some 14 year old Jacuzzi pump/filter combo system. The pool is an above ground ~14,000 gal. I mean, on low it feels like it is still working though, just reading no pressure.

    What does this mean? Or is this normal?

    Thanks for the help

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

    Re: Pool pressure shows 0 psi on pump "low speed"

    Pretty much normal. You see movement in the skimmer and flow from the returns, right?

    You might also try the search box for something like zero pressure variable speed.
    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
    svenpup's Avatar
    Join Date
    Nov 2009
    Location
    Sacramento, CA
    Posts
    835

    Re: Pool pressure shows 0 psi on pump "low speed"

    Reading zero pressure on low speed is totally normal.
    TFP Method Advanced Intermediate
    • 17,500 gallons - In Ground - Plaster - Hayward Swimclear 3020 Cartridge Filter - Sta-Rite Max-E-Glas Main Pump upgraded with A.O. Smith B2980 E-Plus New Centurion Two-Speed Motor - Polaris 280 Cleaner with Polaris PB4-60 Booster Pump - TightWatt2 Timer - Taylor K-2006 Test Kit - Pool Pilot Digital Nano SWCG

    Helpful Links: Pool School, BBB for Beginners, How to Shock (hint...it's a process not a product), Chlorine/CYA Chart, Jason's Pool Calculator

  4. Back To Top    #4
    bobodaclown's Avatar
    Join Date
    Apr 2011
    Location
    Lakeland, FL
    Posts
    2,351

    Re: Pool pressure shows 0 psi on pump "low speed"

    Yeap, Normal. Enjoy the savings!
    17K Kidney Shaped Pool Concrete (Diamond Bright) Pool, 3/4 hp 2 speed 115V Sta-rite Duraglas PEA5D-180L/P2R5D-181L (Impeller C105-92PS Diffuser C1-216P), 1.5 piping, Pentair CC100 Filter , Heat Siphon 100K BTU Heat Pump Pool Heater, Flow meter Blue White Flowmeter Model No. F-30150P, Hayward Astrolight SP0581N, SWCG CalimarTitanium Edition TE45 , Dolphin Nautilus Plus with CleverClean, Lakeland Florida

  5. Back To Top    #5

    Join Date
    Mar 2017
    Location
    Florida
    Posts
    1

    Re: Pool pressure shows 0 psi on pump "low speed"

    ...but the question is, with the "zero pressure" is it actually filtering?
    Bought a florida pool house that needed updating so my new Variable speed echostar pump was just installed and set up by the installers. I have a 13k gal pool with a spa. He had it the automation to run at 30% from 6a -3p and then at 90% from 3p-6p for the skimmer and floor popups to work.
    Things seemed fine, but then I hired a local chain pool company (pinchapenny) to start up the new salt system and maintain for a while to get things going. The guy came over today, said the salt was fine (but no salt had EVER been added to the pool and the SWG had yet to be turned on because the chlorine level was very high from the previous pool guy). He noticed that the filter pressure gauge was "zero" and implied that it was not filtering anything at that speed and should be turned up.
    Who's right?
    I tend to think that the water is being circulated/ filtered and exchanged, just at a lower rate, saving electricity.
    Im new at this, learning much more that I ever wanted to know about pool maintenance and chemistry. And I have questions. So many questions!
    Thanks!

  6. Back To Top    #6
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    Location
    DFW, TX
    Posts
    23,994

    Re: Pool pressure shows 0 psi on pump "low speed"

    You are correct. The water must go through the filter. My filter shows 0 psi 90% of the time and my pool is perfectly clear. So, it is clearly working. Sorry,
    TFP Moderator
    If TFP helped you or saved you money - Become a TFP Supporter! <--Click here
    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

  7. Back To Top    #7
    bobodaclown's Avatar
    Join Date
    Apr 2011
    Location
    Lakeland, FL
    Posts
    2,351

    Re: Pool pressure shows 0 psi on pump "low speed"

    Yes, you are correct. Ask away. We're here to help, and our rates are much better. This is one of those cases where you get much more than you pay for.
    17K Kidney Shaped Pool Concrete (Diamond Bright) Pool, 3/4 hp 2 speed 115V Sta-rite Duraglas PEA5D-180L/P2R5D-181L (Impeller C105-92PS Diffuser C1-216P), 1.5 piping, Pentair CC100 Filter , Heat Siphon 100K BTU Heat Pump Pool Heater, Flow meter Blue White Flowmeter Model No. F-30150P, Hayward Astrolight SP0581N, SWCG CalimarTitanium Edition TE45 , Dolphin Nautilus Plus with CleverClean, Lakeland Florida

  8. Back To Top    #8

    Re: Pool pressure shows 0 psi on pump "low speed"

    Pressure varies by the square of the difference ratio. At 1/3 the rpm, the pressure is 1/9th of the pressure at full speed. Also, the typical filter pressure is -2 psi when off.

    If the full speed pressure is 16, the 1/3rd speed pressure will be about 0 psi.

    As long as the flow switch on the chlorinator stays closed, you're probably good.

    If you feel good suction and return flow, you're good.

    If we assumed that your system woud be close to equivalent to 200 ft of 2" pvc pipe, a 2 psi pressure (0 gauge) would cause about 35 gpm flow rate.

    To determine your filter pressure with the pump off, measure the height of the gauge above the pool surface and divide by -2.31.

  9. Back To Top    #9

    Join Date
    Nov 2015
    Location
    Ok ok
    Posts
    811

    Re: Pool pressure shows 0 psi on pump "low speed"

    My filter shows zero pressure all the way up till the RPMs on my pump get ~2000. In any case, every square drop of water goes through filter.


    ~14K gallon - AquaRite AQR15 SWG - pool Newly plastered on April 9 2016
    TF100 kit - STA-RITE SYSTEM3 Modular Media Filtration - Model S8M150
    Pool water supply from on site water well = CH of ~350 and TA of ~350
    Doheny's Discovery Automatic Robotic Cleaner/Pentair Model 011018 VS Pump
    Sundance Altamar Hot tub separate from pool / central Oklahoma

Posting Permissions

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