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Thread: Iffy temperature sensor on P4 panel?

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    Iffy temperature sensor on P4 panel?

    I removed the pool cover yesterday and fired up the pool after a long winter. No water issue and no leaky pipes!

    I'm however having an issue with my outdoor temperature probe used by my P4 panel. Yesterday, it read "+30F" so it turned on the pump automatically. I figured maybe it needs to warm up after winter.. it then displayed the proper temperature an hour later (+72 or 75F). It was fine this morning but I now went to take a quick look at the panel and the pump is still running because it's displaying an outside temperature of +30F so it enabled freeze protection even though it's +70 something outside.. . I had no issues with it last year.

    Anyone seen anything like this? I thought that the temperature probe was a simple thermistor so I'm surprised that it would go bad, then good, and bad again.. I'd do a few tests but my P4 is in a shed along with all my equipment and the probe is a pain to access, especially since it's near the soffit of the routing of it's wire is even worse.. due to that, I figured that I'd ask here first hoping there's some diagnostic more for the temperature probes.

    I guess a pool start-up where everything works fine is too much to expect
    19.5k gallons in ground, P4 panel with turbocell SWG, 1hp Hayward superpump II, sand filter, Heater low nox 250k btu heater, solar cover on rocky roller

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    JasonLion's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    Often that symptom means a loose connection between the sensor and the main unit.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    maxepr1's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    Went through these same problems with my P4 water temp sensor. First make sure to tighten the screws on the block where the wires connect to the board. I fthey look corroded cut them off and strip back some clean wire and reinstall. I found the block in self shorting to ground, so I changed the block and so far so good. I have a copy of the resistance values for the different temps so I rang out the sensor so I ruled that out. My temp was all over the board high, low then sometimes it worked fine. But the messages alway coming up were a bother.
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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    Re: Iffy temperature sensor on P4 panel?

    Quote Originally Posted by maxepr1
    Went through these same problems with my P4 water temp sensor. First make sure to tighten the screws on the block where the wires connect to the board. I fthey look corroded cut them off and strip back some clean wire and reinstall. I found the block in self shorting to ground, so I changed the block and so far so good. I have a copy of the resistance values for the different temps so I rang out the sensor so I ruled that out. My temp was all over the board high, low then sometimes it worked fine. But the messages alway coming up were a bother.
    Would you mind posting these values here? My temperature went back to normal an hour or two later.. I'll doublecheck the connection in the panel.

    Thanks a lot folks!
    19.5k gallons in ground, P4 panel with turbocell SWG, 1hp Hayward superpump II, sand filter, Heater low nox 250k btu heater, solar cover on rocky roller

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    maxepr1's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    I'll post up tomorrow.
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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    Re: Iffy temperature sensor on P4 panel?

    Similar problem....turned out to be broken wire where it connects to sensor. Installer damaged it when installing sensor. Replaced sensor/wire and everything works great.... of course that was after the $800 gas bill!
    IG 24k plaster with overflow spa. Goldline PS-8 SWG. Tristar 0.75 HP filter pump, Polaris 280, large cartridge filter, 400k BTU NG Max-E-Therm HD, SR Smith Turbo Twister, Life Saver pool fence, ORP managed.

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    maxepr1's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    Ok here's the values. Tried to get the normal values for normal temperatures, if you need one the isn't there PM me and I'll send it to you.



    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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    Re: Iffy temperature sensor on P4 panel?

    Thanks. Weirdly enough, my probe has been fine for the last two days.. I saved these resistance values as reference though.
    19.5k gallons in ground, P4 panel with turbocell SWG, 1hp Hayward superpump II, sand filter, Heater low nox 250k btu heater, solar cover on rocky roller

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    maxepr1's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    Sounds like a connection problem. I would cut the ends off and strip clean wire and screw in into the terminal block. If it continues your terminal block is shorting.
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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    Re: Iffy temperature sensor on P4 panel?

    What does the sensor and connection to the main board look like? I'm trying to trouble shoot inaccurate temp panel readings compared to what my heater is showing.
    27x14x6 IG Salt Water Pool
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    maxepr1's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    On my board it's in the upper left corner. The block is green with the wires running up the low voltage channel. Of course you have to take off the front cover to see this.
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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    Re: Iffy temperature sensor on P4 panel?

    What's required to take the front cover off? anything difficult? First-time pool owner and P4 panel user here so bare with the dumb questions lol
    27x14x6 IG Salt Water Pool
    Raypak 206 NG Heater
    T-Cell-9 Super Chlorinator
    Hayward Tristar 1/2 HP Pump
    Aqua P4 Logic System w/AquaPod
    Cartridge Filter System

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    maxepr1's Avatar
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    Re: Iffy temperature sensor on P4 panel?

    Shut off the power and unplug the cell. Then straight slot screwdriver and 3 screws and the panel will come off. A small screwdriver and some scotch brite you can remove the wires and clean them with SB to remove any corrosion and reinstall and see if that works first. If not it gets more complex. And it requires a multimeter and a little knowledge. Try cleaning first. Then I would just remove the junction and replace it. It just pulls off.
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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