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Pressure Valve going off, bar pressure over 2.0 Pstat issue likely but.....

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  • Pressure Valve going off, bar pressure over 2.0 Pstat issue likely but.....

    Guys

    I have , through this forum, managed to do quite a bit of home maintenance etc however I'm now looking to, sigh, send my machine in for a "please fix it!" service.

    La Scala Butterfly approx 3-4 years old. Descaled heavily yesterday and replaced gasket. Have replaced the brainbox (that was a nice surprise just post 12 month warranty....) and recently (24 months ago) replaced pasts (coffee parts misc-700571 1/4inch BSP thread Asso Pressurestat ).

    Now I have not used the machine for 12 months or more. Reasons are likely to be the reason i'm now posting this. I'm not sure the pstat I purchased is the 'right' and 'appropriate' one - I may have not read or understood an article here in the forum about Pstat replacement.

    Pressure is going well over 1.5 bar and i've seen it get to 2.3 before the pressure valve just goes off like all hell has broken loose - really nice to surprise my wife when I wasn't home!
    The Pstat is a well recognised one and I've kept it back to it's lowest setting (as in I have not turned it up!).

    Thoughts?

    There was a sh^t load of scale in the machine (no water coming through group head) and I've done a decent job descaling and now water all coming through etc.

    But i need help before I just go and get reemed hard by the service centre :-(

    After this then I'll want to talk moving up from my rocky grinder to something a bit more control and better.....

    Cheers

    Stu

  • #2
    <bump for your thoughts please> I'm trying to hold back from sending this across to service....

    Comment


    • #3
      pressure stats are pretty basic, i had same issue with an early machine and it was the pstat.. maybe you'rs is just badly calibrated? or faulty, or maybe caught some scale?

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      • #4
        Thanks AG. I 'hope' it is not badly calibrated - I cannot turn it down any less so chances are either a) faulty b) need to re-descale again. I will try b) first and then go to a).

        Qu - if descale again should i first just take the pstat out clean the connections and fittings, then place back , then descale.

        Thanks and open to other suggestions to.

        stu

        Comment


        • #5
          Thanks AG. I 'hope' it is not badly calibrated - I cannot turn it down any less so chances are either a) faulty b) need to re-descale again. I will try b) first and then go to a).

          Qu - if descale again should i first just take the pstat out clean the connections and fittings, then place back , then descale.

          Thanks and open to other suggestions to.

          stu

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          • #6
            Ok so I need some assistance identifying this problem part (see attached). When re-doing descaling today when machine turned on and both steam and water taps open I noted water coming out of the valve (see attached). This was despite very little if any pressure build up. SO looks like I've stuffed this up and need to replace it. Can someone out here id the part I need. La Scale Butterfly machine. Once I get this part then I'll have to go through the process again I've isolating the issue.

            Thanks
            Attached Files

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            • #7
              Ok so thanks to Alan Frew website at C4C I now know it is the Vacuum Breaker that is at fault (for the current issue). Coffeeparts I'm having trouble locating this.

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              • #8
                While you wait for your replacement anti vac valve to arrive, you can remove your one and replace the o-ring, there is not much to them. An automotive bearing or parts shop should have one for a few cents.

                For the entire valve replacement you just need the thread size and note if you have a height restriction. You should be able to find then in coffee parts under misc parts.

                Also, unless there is pressure in the boiler, the anti vac valve will not be shut and will leak.

                Cheers

                Comment


                • #9
                  Forgot to add, the anti vac valve will not solve the boiler over pressure problem you are experiencing.

                  Cheers

                  Comment


                  • #10
                    Most machines leak out of the anti vac valve during descaling. It is located below the steam and water tap outlets so naturally the water will exit through the valve before the taps. It is unlikely that the valve itself is damaged.
                    If you could hear a hissing from it when the boiler is under pressure then the o-ring would need to be replaced. It is a standard silicone or viton o-ring, the same as is used on nylon tubing you find inside most domestic machines.
                    Cant remember the measurements off the top of my head. 8mm x 4mm I think.

                    Easy way to deal with the valve when descaling is to grab the top of the pin and lift it up until you can feel the o-ring seat and then use locking pliers or the like to lightly clamp the lower part of the pin. This will hold the valve shut so it doesn't leak.

                    Re: original problem.
                    The butterfly should use a ma-ter pressurestat which has an external switch. Not sure the Asso is ideal for it. This may be where your problem lies.
                    Source a ma-ter T125 from coffeeparts if you have no luck with your current plans. Good thing about the ma-ters is that the switch can easily be removed and replaced for a few dollars. Saves having to replace the whole pressurestat each time.
                    Last edited by noidle22; 30 August 2014, 10:27 PM. Reason: more info

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                    • #11
                      Thanks for your response re the valve and pstat. The pstat is likely the problem so will order the 'correct' one as pointed out. Fingers crossed this resolves everything then new beans try the rocky then replace it with something better. Then descale the Silvia and with it and rocky put it up here.

                      Many many thanks

                      Stu

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                      • #12
                        Awesome news! Installed new pstat and vacuum valve and descaled and working.....

                        However very very slow leak under group head , exhaust valve can't recall correct name. Ground some old but sealed beans nothing coming out. Water came out portafilter which makes me think need 0.5mm additional gasket. Little bit of water coming out near manual lever which makes me worried seals need replacing.

                        Went through numerous step up in grind and still nothing coming out, pucks all wet but dense and firm.

                        Thoughts? I'm open to them.

                        Comment


                        • #13
                          I am an idiot! Used the wrong gasket replacement, not realising I had several spare gaskets for my old Silvia I assumed wrongly I purchased these for the Butterfly. Makes sense now. Muppet!

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