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Thread: Problem with Pool Pilot and Pentair Master Temp 300 Pool heater

  1. Back To Top    #1

    Join Date
    Apr 2015
    Minneapolis, MN

    Problem with Pool Pilot and Pentair Master Temp 300 Pool heater

    Okay, so my Pool Pilot Digital Nano had a message reading, "Check Flow Error, Purity Off". So I cleaned the manifold screen completely, took apart the manifold, flushed with water, and cleaned the sensor with a mix of muriatic acid and water per the instructions. It still will not produce chlorine. However, when I switch the spa valve on so that water is redirected only through the pool heater, then the error message goes off and it produces Chlorine. The only problem is that it switches the pool heater on. I don't understand the problem. The only thing I haven't done and am reluctant to do, is to take apart the trisensor. I took the two little screws off, and I couldn't budge it at all.

    Also, when I turn the spa valve to off the off position, and the water then goes partly through the heater and partly directly to the pool through the manifold, the error message comes back on, and now the pool heater won't turn off. Well it turns off but the LED display shows 256 degrees. It will not respond to pressing the heater off button.

    So what I've done for now is I've turned the breaker off to the pool heater, and turned the spa on valve and the water pressure all going through the spa seems to be enough to keep the pool pilot on. I have it producing 80% chlorine. Is it possible that that much chlorine is requiring too much water flow?

    I'm at a loss for what to do at this point.

    Any help would be more than appreciated.

    Thank you all very much.


    I am Jerry from Florida and I have a rectangle shaped in ground pool with square spa at one end. I have 25000 gallons.

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Problem with Pool Pilot and Pentair Master Temp 300 Pool heater

    Welcome to TFP!

    How is the plumbing laid out? Perhaps a photo would be the simplest thing. In particular, when you divert water away from the heater, is it also diverted away from the SWG cell?

    It is also a good idea to try cleaning/backwashing the filter, as well as the skimmer basket and pump strainer basket, when you get a check flow error.
    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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