HPC plusair SM6 screw compressor kaput

  1. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    I've had this for about 4 years, it was free from a school that no longer required it, it only had 20 hrs on the clock, it now has only around 35. It worked fine last time I used it.

    Now the motor starts up, it gets up to speed, then stops. Before you could here the pitch change as suddenly the motor was under load, it is at this point it stops, so presumably some valve kicks in, or should kick in?

    I'm thinking that this may be a problem of lack of use. I have a small oil free quiet compressor for small hand tools like air pinners, I only use the HPC on the blaster, bigger air tools, car tyres etc.

    Anybody know much about these and can point me in the right direction? I haven't had a good play around yet so I may find something obvious but any clues based on experience very welcome :)

    20190519_212829.jpg

    Cheers
    Andy
     
  2. scottmk1

    scottmk1 Forum Supporter

    Messages:
    963
    Location:
    Scotland
    Possibly the unloader valve not closing once its up to speed so sensing a fault and shutting itself down?
     
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  3. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    Sounds very plausible, now which bit is the unloader valve ? :)

    Cheers
    Andy
     
  4. scottmk1

    scottmk1 Forum Supporter

    Messages:
    963
    Location:
    Scotland
    Hard to tell from your photos but it's sometimes on the compressor outlet before the air goes through oil and water separators dryers etc

    What's that solenoid looking thing on top of the compressor?
     
  5. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    I shall have a look tomorrow, I'm on kids bedtime duties tonight.
     
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  6. Brad93

    Brad93 M J B Engineering

    Messages:
    5,637
    Location:
    Essex
    Seriously good but of kit HPC compressors.

    Worth getting an engineer out I’d say.
     
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  7. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    There's a company not far away in Bolton I'm talking to if I can't fettle it. It won't be cheap but it doesn't owe me anything and keeps pace with the blast cabinet, and it's very quiet so definitely a keeper :)
     
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  8. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    I've had a good look around, started it up with the covers off, nothing seems untoward yet it stops. I could start poking about with a meter but with no manual or diagrams it would be a shot in the dark so I've got somebody coming around early next month to fettle and service it.

    Cheers
    Andy
     
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  9. StevenHill New Member

    Messages:
    2
    Location:
    Britain
    On the unloaded valve there will be a switch on the other side of where you have taking the picture, on start up the compressor takes in a little air and this switch opens for the Compressor to kick in, if the switch doesn’t open the compressor will shut down due to it thinking there’s no air and the compressor is going the wrong way. You can take off the 2 cables going to the switch and link them together. Hope this helps
     
  10. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    Welcome to the forum, and thanks for the info, I shall have a look in the morning.

    Cheers
    Andy
     
  11. brewdexta

    brewdexta Member

    Messages:
    3,654
    Yorkshire
    It's fixed, took a while but I wasn't in a rush. Turned out to be a contactor coil so the the second or delta stage wasn't kicking in when called upon.

    Now to get a blast pot and get the dexta tinwork and the old quad trailer blasted.
     
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