1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Nilfisk 140.3 pressure washer fix (likely similar for other makes and models)

Discussion in 'Tools and Materials' started by tobers, 19 Apr 2019.

  1. tobers

    tobers

    Joined:
    19 Mar 2005
    Messages:
    28
    Thanks Received:
    8
    Country:
    United Kingdom
    I bought my Nilfisk 140.3 pressure washer after recommendations on here.

    It was great for about a year. Then it randomly wouldn’t run, then it would, then it wouldn’t etc. Extremely frustrating. The symptom was that, with the washer plugged in and on, and water connected, when switching on the normal loud thrumming pump sound was sometimes absent. It normally thrums for a second or so when switched on.

    Sometimes though, it would thrum when switched on. And then it would work fine for a while ie you trigger the lance and the pump triggers and it power washes anything very nicely. Then you let go of the lance trigger, move around the car/patio etc and when you pull the trigger again the pump just wouldn’t start. Wait a bit, kick the machine a few times, and it then might start, but often wouldn’t. Random and intermittent. Very frustrating.

    Today I decided to sort it out. I’m posted here to help any other victims to save some time. I couldn’t find anything on the internet to help.

    I figured there must be a switch somewhere that sensed water pressure from triggering the lance, and then switched the pump on.

    I basically unscrewed any visible screws to remove the handle, covers, underside. Basically stripped. First thing to check was the on/off switch. Some of the contacts were a bit loose but the switch worked fine (multimeter continuity test). I tightened up the crappy spade connectors a bit. Re-tested - same problem.

    The pump seemed to spin OK. There was no debris in the inlet. Could be the capacitor (large white cylinder near the on/off switch. But that looked fine and would either run or not - it wouldn’t cause the intermittent issues I was experiencing.

    Next to the water inlet was a little white plastic rod sticking out. I couldn’t figure out what this was.

    After further investigation, the panel that the power connectors are fixed to has a little microswitch attached to a cable that goes up to the on/off/capacitor switch connector gang. This microswitch is triggered by the little white plastic rod. But it’s usually under a cover that you need to expose by removing another screw (the cover that the water inlet goes through).

    Weirdly, there is nothing to hold the microswitch assembly onto the white rod. Figuring this microswitch sensed pressure on the inlet and triggered the pump (from the wiring diagram), I decided it was the cause of the intermittent problems I’d been having. I have no idea why it doesn’t screw or bolt in place. It’s so obvious it will dislodge and cause problems.

    So I cable-tied the microswitch in place, reassembled, and everything now works perfectly!

    As it happens, I need not have removed every screw and plastic piece. I could have just removed the two screws holding the front cover on (under the unit) and then the additional screw for the panel covering the inlet valve and I would have been able to get to the micro switch.

    I hope this helps someone.

    Here’s the culprit

    [​IMG]

    Hmm - if you can’t see the image try this link:
    https://tobinators.com/blog/wp-content/uploads/2019/04/img_2673.jpg
     
    • Thanks Thanks x 6
    • Like Like x 3
  2. Sponsored Links
  3. ktuludays

    ktuludays

    Joined:
    10 Nov 2008
    Messages:
    339
    Thanks Received:
    52
    Location:
    Lincolnshire
    Country:
    United Kingdom
    Great post. I have a nilfisk and whilst I haven't had the issue you describe I'll keep your post in mind if I ever do.
     
  4. stealthwolf

    stealthwolf

    Joined:
    20 May 2015
    Messages:
    537
    Thanks Received:
    34
    Location:
    Birmingham
    Country:
    United Kingdom
    I have the same model and had an issue with it only working intermittently. Turns out it doesn’t like hozelock autostop connectors.
     
    • Like Like x 1
  5. cdbe

    cdbe

    Joined:
    22 Nov 2009
    Messages:
    778
    Thanks Received:
    114
    Location:
    Oldham
    Country:
    United Kingdom
    Same here. I'll file this one away.
     
  6. Michael G P

    Michael G P

    Joined:
    5 Apr 2020
    Messages:
    2
    Thanks Received:
    0
    Country:
    United Kingdom
    Just the job...thank you
     
  7. Kempouk

    Kempouk

    Joined:
    2 May 2020
    Messages:
    3
    Thanks Received:
    0
    Country:
    United Kingdom
    (long quote removed)

    Hi,
    New here and come across your advice as my pw was playing up so followed your NFO but with no joy,
    So I did some further investigating on my machine and found that the pump worked just fine with the pressure switch housing removed from the white rod.
    This showed me that the white pressure rod was stuck in the out position so as soon as the pressure switch was connected the switch was activated telling the unit not to run as it was under pressure.
    I took a pair of long nose pliers and with a fair bit of force pushe the white rod back into the housing.
    This resulted in a click as the rod become free and retracted back into the unit leaving about 15mm protruding from the unit.
    This inturn disengaged the pressure switch allowing the pump to run as it should .
    So this white rod is prone to sticking and in the out position will render the unit usless.
    I then put a tiny bit of cilicone geese on the rod and cable ties it back in position using your advice.
    To access this you just need to remove the two hex scews from the underside of the unit holding the front feet on the machine,
    Then lift the blue cover off,
    Then remove 1 hex scrw covering the pressure switch housing and the black pressure switch is located here.
    The can be removed by pulling hard and gently up and down as it pops into place.
    One the switch is removed you can see the white pressure rod,
    This is the problem and needs a pair of long nose pliers and some force to pop it back I to position,
    This rod should be protruding about 15mm.
    You can flick the power switch on and off to make sure the switch is now free and working as it should.
    Then put your unit back together.
     
    Last edited by a moderator: 2 May 2020
    • Like Like x 1
  8. Sponsored Links
  9. Michael G P

    Michael G P

    Joined:
    5 Apr 2020
    Messages:
    2
    Thanks Received:
    0
    Country:
    United Kingdom
    Great update....thank you!
     
  10. sparkymarka

    sparkymarka

    Joined:
    16 Feb 2011
    Messages:
    7,917
    Thanks Received:
    1,205
    Location:
    Sheffield
    Country:
    United Kingdom

    What type of GOOSE was that ?
     
  11. Kempouk

    Kempouk

    Joined:
    2 May 2020
    Messages:
    3
    Thanks Received:
    0
    Country:
    United Kingdom
    It's a silicon goose lol.
    I'm always getting typos using my phone.
    Lol
     
  12. sparkymarka

    sparkymarka

    Joined:
    16 Feb 2011
    Messages:
    7,917
    Thanks Received:
    1,205
    Location:
    Sheffield
    Country:
    United Kingdom
    Made me chuckle ...
     
  13. Kempouk

    Kempouk

    Joined:
    2 May 2020
    Messages:
    3
    Thanks Received:
    0
    Country:
    United Kingdom
    And me when you pointed it out,
    Lol
    Apparently they are quite rare.
    :ROFLMAO::p
     
Loading...

Share This Page