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Silvia Over pressure valve diagnostics

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  • Silvia Over pressure valve diagnostics

    Hi,

    have a brew problem with my Silvia (~3yo), and I think its the OPV. Basically I get over-fast flow with a very fine grind, so I think the OPV is stuck/broken and I want to know
    a) diagnosis: how can I be sure its the cause of my problem,
    b) home repair: can anyone point me to instructions on ordering the part and changing it myeslf, or
    c) outsourced repair: is there a repairer in the Mel area who can do it relatively cheaply?

    Basically, the problem is it flows too fast. The grinder has new blades, is one step above zero, and only gets pours with good-ish flow (resulting in roughly the right volume, at 20 secondsish) with about 19-20g of coffee packed into the double basket. Packed! Too much pressure Im sure. Im using good, fresh beans, from a number of sources to cross-check. (different blends, origins, roasts etc.)

    A friend with a Silvia says the grind looks fine - he doesnt believe its the grinder (thankfully, or Id have to chuck it or get it rebalanced or something crazy). I also cleaned out the grinder and used teflon, with no noticeable result, so I think thats not the problem. The problem came about very suddenly one day, which is why I think some part of the silvia is broken.

    My thoughts on diagnosis: I assume could check with a portafilter gauge (or a repairer could), or there may be another flow type test?

    I guess it could be another mechanical part I dont know about? no idea.

    On repair: I dont have too many tools, Id be inclined to hand this over to someone else if theres a good suggestion.

    Sorry for the essay - just trying to be complete. Any suggestions appreciated!

  • #2
    Re: Silvia Over pressure valve diagnostics

    By the way I have done a few searches. but mostly I get links about adjusting brew pressure (assuming the OPV is still working)

    Also, its the original Silvia, not the one with the adjustable OPV.

    Comment


    • #3
      Re: Silvia Over pressure valve diagnostics

      If you get your grind fine enough it should choke Silvia, have you tried getting it as fine as possible? What sort of grinder, Rocky?

      Comment


      • #4
        Re: Silvia Over pressure valve diagnostics

        Its a rocky.

        It is as fine as possible, Im pretty sure of that. New blades, one notch away from touching.

        Yeah, it USED to choke the coffee machine... and the grind looks fine, and I changed the blades even just to make sure, so Im leaning more towards the machine having something wrong.

        Seriously, as fine as possible and as much coffee as possible, packed very hard, and then the portafilter only JUST screws into the group head becuase of the quantity. And 20 second pours.

        D

        Comment


        • #5
          Re: Silvia Over pressure valve diagnostics

          hey dhm,
          not necessarily related to the opv but if you updose too high, youre likely going to get channelling which may also play a part in the shot extracting too quickly.
          but if you think that there has been a sudden change to pour times, it might pay to take it to a site sponsor who knows one or two things about miss silvia. they should be able to determine the max setting for the opv (adjustable or not).
          good luck

          aaron

          Comment


          • #6
            Re: Silvia Over pressure valve diagnostics

            DHM,

            You can get a rough idea of the OPV setting by measuring the output of the OPV outlet hose, whilst running with a blind filter.
            There is a graph on the ULKA pump website that shows the expected flow rates for each model: on Silvia it is an E5 [IIRC]

            THere are quite a few posts here about this so try and do a search with ULKA in the field.

            The test gives only a rough guide, proper pressure measurement at the group is a better method.

            I dont think the OPV is necessarily the problem, its basic function is to protect the pump. Your puck should determine the pressure.

            Id look further into your grinder, eg:

            1. Is the grind you are producing slightly clumpy, usually some clumping suggests you are in the espresso zone.

            2. Buy some preground coffee from a reputable source who will know what to grind it at [supermarket grind is wrong wrong wrong for espresso]

            3. If the grinder is reassembled with the burrs even slightly askew, then the "burr touch-point" will prevent a finer setting.

            Comment


            • #7
              Re: Silvia Over pressure valve diagnostics

              HI DHM,
              I am having the exact same problem as you are, I was just about to post the exact same issue!! I too have my grinder on all but the zero setting and the grind looks fine (its worked perfectly for over a year on this setting).
              Please let me know if you have any luck with a fix, it would be really apprecaited.
              Cheers
              Scott

              Comment


              • #8
                Re: Silvia Over pressure valve diagnostics

                By the way, problem solved. My local coffee supplier ground me some coffee, which I zipped home and sure enough, the coffee came out perfectly. It was clearly more fine than my finest grind anyway. So problem isolated - it was the grinder.

                He offered to have my machine sent out to his own personal repair guy, and the news I got today is that one of the support struts in the machine is broken, causing vibrations and unevenness in rotation.

                Repair cost is less than half the replacement cost, so Im getting it done.

                dana

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                • #9
                  Re: Silvia Over pressure valve diagnostics

                  [split] [link=http://coffeesnobs.com.au/YaBB.pl?num=1249027691/0#0][splithere][/link][splithere_end]

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