Results 1 to 7 of 7
Like Tree3Likes
  • 1 Post By Dimal
  • 1 Post By Javaphile
  • 1 Post By Javaphile

Thread: Pressure Stat failure-Possible reasons.

  1. #1
    Senior Member
    Join Date
    May 2014
    Posts
    548

    Pressure Stat failure-Possible reasons.

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello Coffee Lovers,
    Just a quick request to those of you how may know:contacts of pressure stat (Rancillio S10/CD two group) failure from severe arching/pitting (see photo).
    Can a failing magnetic relay module contribute to the seriously wrecked pressure stat contacts,or is the problem just due to increasing resistance/heat to final and complete failure of the contacts themselves.
    Will a replacement set of contacts solve the problem,diaphragm/pin/membrane seemed fine and still very pliable/flexible?
    Thanks for your support.
    Cheers,
    Mick.
    Arced contacts .jpg

  2. #2
    TC
    TC is offline
    .
    Join Date
    Oct 2004
    Location
    Melbourne
    Posts
    14,665
    I call that a shagged pressurestat. The fix? Buy a new one.

  3. #3
    Mal Dimal's Avatar
    Join Date
    Oct 2004
    Location
    Warwick, QLD
    Posts
    16,869
    G'day mate....

    You'll probably find that the mechanics of the Moving Contacts section isn't operating as 'snappily' as it once did and as a result, the contacts are not breaking as cleanly as they should. Could be down to a buggered diaphragm or just mechanical wear and tear.

    This allows an electrical arc to be maintained for excessive amounts of time and due to the extremely high temperatures of the arc itself, the surfaces of the contacts start to erode due to vaporisation of the parent metal. This doesn't happen cleanly and after a while, the contacts can even weld themselves together... Not a good thing at all.

    Unless you just want to refurb the p/stat as an exercise for experience, a new one is probably the best solution as Chris suggests. No need to opt for the original though, you can get a decent quality narrow band p/stat and connect that in conjunction with suitable SSR(s) to avoid the situation in the future...

    Mal.
    mulquemi likes this.

  4. #4
    Senior Member
    Join Date
    May 2014
    Posts
    548
    Mal,
    Thanks for your reply, thats what I thought, I will proceed with this rebuild, if just for the challenge and as to it's viability.
    Cheers,
    Mick

  5. #5
    Super Moderator Javaphile's Avatar
    Join Date
    Dec 2004
    Location
    Earth!
    Posts
    15,663
    And if you use them long enough this is what they'll end up looking like:

    PB020639-resize-1280.jpg PB020628-resize-1280.jpg


    Java "Burned what?" phile
    Andy likes this.
    Toys! I must have new toys!!!

  6. #6
    CoffeeSnobs Owner Andy's Avatar
    Join Date
    Mar 2004
    Location
    Internet
    Posts
    16,843
    Blog Entries
    1
    whoa... that looks nasty Java and make the ones in Mick's initial picture look brand new.

  7. #7
    Super Moderator Javaphile's Avatar
    Join Date
    Dec 2004
    Location
    Earth!
    Posts
    15,663
    Yeah I took those pics a bit over 4 years ago when I had to rebuild the contactor in in my M28: http://coffeesnobs.com.au/brewing-eq...aced-ssrs.html


    Java "Fun with electricity!" phile
    Dimal likes this.
    Toys! I must have new toys!!!



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •