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KARCHER pressure washer - motor fault

Discussion in 'Appliances' started by pen4uk, 1 Jul 2020.

  1. pen4uk

    pen4uk

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    Hiya you knowledgeable people,
    OK, I have a KARCHER 390 old model. its been fantastic up until now. First issue was, it suddenly stopped working done some digging and found it had a leak on one of the cylinder head seals ok replaced that stopped the leak. All good I thought but no. With the cover off water on full, and hold the trigger fully open and push the fan on the back of the motor it springs into life BUT as soon as I let go of the trigger it will not start again until I push the fan and then its fine until I release the trigger then back to square one again. is it the Brushes? if yes how do I do that ?
     
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  3. Burnerman

    Burnerman

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    Check out the motor capacitor first, look for burning or any discolouration.
    These components instruct the motor in which way to spin, and if its faulty this is the symptom you get.
    John :)
     
  4. jj4091

    jj4091

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  5. pen4uk

    pen4uk

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    Hiya John, I think you've hit the nail on the head.
    When I prod the fan it spins to the left and when I do it again it spins to the right.
    Where is the Capacitor located? Would it be in the little black plastic box on top of the unit.
    Thanks for your help
    regards Colin
     
  6. Burnerman

    Burnerman

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    A motor capacitor is generally a shiny aluminium cylinder (closed ends!) often bolted to the motor itself or certainly nearby. It will be marked with its working voltage and capacitance measured in microfarads or uf.
    Typical voltage could be 400v and capacitance 4uf.
    We’d need a photo for more recognition I think.
    John :)
     
  7. pen4uk

    pen4uk

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    Thanks for that I will have a look in the morning when I get home from work.
    many thanks
     
  8. SFK

    SFK

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  9. pen4uk

    pen4uk

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    I couldn't wait until the morning John
     
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  11. Burnerman

    Burnerman

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    That’s pretty high for a motor start cap.....oh well! Plastic or metal, the markings are the same.
    John :)
     
  12. pen4uk

    pen4uk

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    Hi John,
    I've located it,
    on my unit it has this,
    Icar Italy Ecofill
    WB 40200
    20 UF
    AC 400V
    And the closest I've found is,
    Icar Italy Ecofill
    WB40400
    40UF
    AC 400
    is this any good?
     
  13. Burnerman

    Burnerman

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    Hmmm certainly the working voltage is fine but the capacitance -40 against 20uf.
    I’m afraid I’m not able to comment if that is ok or not and no idea what difference it would make but I’d prefer to get one nearer the original rating.
    John :)
     
  14. SFK

    SFK

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    Not important> Icar Italy Ecofill
    Not important> WB 40200
    Most important> 20uF (must be at this value)
    Make sure at or above> AC 400V (no issues with this being AC450V or AC500V).


    You will want one of these:
    ebay search "Karcher 20uF"
    https://www.ebay.co.uk/sch/i.html?_...0&LH_TitleDesc=0&_osacat=0&_odkw=katcher+20uf

    Or these:
    Google search "Karcher 20uF"
    https://www.google.com/search?client=firefox-b-d&q=Karcher+20uF

    Or if you have the money this is likely to be closest to OEM:
    https://www.espares.co.uk/reviews/es538532

    SFK
     
    Last edited: 2 Jul 2020
  15. Burnerman

    Burnerman

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    Anyone have any ideas what happens if the wrong value capacitor is used?
    John :)
     
  16. SFK

    SFK

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    If the wrong capacitor rating or a poor quality capacitor is used, then the motor will not have the correct phase angle between the current and the voltage, and consequently the motor torque or rotational force will be affected. Depending on the motor load, this may result in a reduction in the motor's overall speed.
    No idea what the tolerance is. Would need to know inductance of motor i presume.
     
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  17. jj4091

    jj4091

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    In the old days if it was a long way out of tolerance the motor would lock up & begin to smoke, probably because of SFK's description
     
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