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Compressor not cutting out

Discussion in 'Tools and Materials' started by opps, 12 Mar 2021.

  1. opps

    opps

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    Hi all

    My (15 yr old) Nardi compressor starts up OK, reaches 7 BAR and stays there with the motor running constantly.

    20210312_164848.jpg

    20210312_164727.jpg

    From what I have read, it sounds like the pressure switch may be faulty.

    A new generic one seems to be about a tenner.

    https://www.amazon.co.uk/214124-Com...2&sprefix=Compressor+presure+,aps,160&sr=8-10

    41pKjYyR-tL._AC_.jpg

    The one above looks very similar but it lacks the female nut where it meets the male part on the tank.

    Mine looks like this

    20210312_174149.jpg

    The other thing I can't work out is how to remove the blue pipe. The amazon replacement seems to have a nut where the blue pipe goes.
     
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  3. HERTS P&D

    HERTS P&D

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    Try pushing the metal shroud around the pipe, while pushed up pull out the blue pipe.

    Andy
     
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  4. opps

    opps

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    Will do, thanks.

    So will the new pressure switch use a nut and olive to connect the blue pipe?

    And any ideas about the tank nut?
     
  5. HERTS P&D

    HERTS P&D

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    The best person to help you is John Burnerman.

    Hopefully he will be along soon.

    Andy
     
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  6. Burnerman

    Burnerman

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    I don't know if you've bought the new switch yet, but have you thought about dismantling the original one? The chances are it'll be bunged up with rust which has occurred over the years. Nothing to really break inside so you have little to lose!
    John :)
     
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  8. opps

    opps

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    I think you might be correct about the rust. When I put my finger in the end of the tank nut it was black. Will try to take it apart if I get the time on Sunday.

    Cheers
     
  9. opps

    opps

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    Update

    I did clean out the old switch but it made no difference.

    I worked out how to remove the blue pipe- once you remove the back of the switch there is what looks like a toy black spanner (see middle of photo)

    20210411_120025.jpg

    The problem I now have is the nut (connected to the old switch) that runs from the switch unit to the reservoir. I have no idea how to remove it and fit it to the new switch. Initially, I assumed that I just needed to put an Allen key in it and unscrew it, but none of my metric or imperial Allen keys seem to grip anything. The hole inside looks round. The nut can be seen in image 2 and 4.

    I guess I will need to order a male to female connector. Does anyone know what size they are?
     
  10. Harry Bloomfield

    Harry Bloomfield

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    Pressure switches are usually adjustable - have you tried adjusting it to a lower setting?
     
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  11. opps

    opps

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    I have used the red twisty knob thing to reduce the required pressure. It reaches the lower level and still keeps on running.

    I was under the impression that the adjustment on the switch was related to the pressure at which the compressor kicks back in. Are you saying that the lower level might have become higher than the setting defined by the regulator dial?
     
  12. Harry Bloomfield

    Harry Bloomfield

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    That was my thoughts, that the switch had maybe drifted in calibration. It switches on when the pressure falls, off when it rises to the setting - with a bit of hysteresis in between. I seem to remember mine doing the same and found there was a microswitch which had failed.
     
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