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  1. #1
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    Fluctuating Kriwan resistance value



    Scroll ZH56K4E-TWD-524, Air/Water heatpump, installed begin 2016.
    Kriwan fault, sometimes 5:day, sometimes no shut down in some days.
    LP and HP are very stable (-1°C, 52°C), SH also stable
    Current Stable 14,2 en 14,8A.
    Bridged Kriwan, disconnected sensors and measured internal sensors.
    Resistance varies from 1kohm to 30 kohm within 30 seconds
    Sounds varies as well.

    Link
    https://www.youtube.com/watch?v=jGVf...ature=youtu.be

    What do you think is happening?


    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  2. #2
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    Re: Fluctuating Kriwan resistance value

    It looks like thermistors inside are faulty. I recommend installation of electronic motor protection.

    https://www.schneider-electric.com/e...verload-relays

    Also, I would advise usage of discharge pipe manually reset thermostat of 110°C in series with that thermal overload.
    Last edited by nike123; 15-11-2017 at 12:33 PM.

  3. #3
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    Re: Fluctuating Kriwan resistance value

    Thanks Nike 123... discharge temperatures stay also very stable around 95°C.
    SH is also low, so windings are cooled very good I suppose.
    Overload was already installed.
    We suspect also erratic thermistors.
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  4. #4
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    Re: Fluctuating Kriwan resistance value

    Thermistors are semiconductors end when they are erratically (jumping in values) then it is certain that they are faulty, since temperature cannot change that fast and fluctuate that much.

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