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Via venezia leaking pressure?

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  • #16
    Originally posted by thebrownbean View Post
    bumping this thread. I recently noticed that my Via Venezia (10 months old) seems to build up excessive pressure at times at the group head.
    On some occasions, when I remove the portafilter, there would be a burst of pressure and the wet coffee grounds would splatter around the tray area.

    Would it be anything to do with the grind size? Would things improve if I change from using a pressurized portafilter, to a non-pressurized one? Thanks and appreciate any help on this.
    Originally posted by mulquemi View Post
    SKU/Part #: 128452403 Check this part on your machine,seems yours is blocked as the pressure relief should come into play.

    Cheers
    Mick
    What makes you think "excessive pressure" is the problem?

    A quick google suggests the Via Venezia doesn't have a three-way valve. That right? In which case, there is only one path for fluid to exit (which is what causes the pressure to fall) - via the puck!

    A finer grind creates greater resistance to flow and thus could well slow the "depressurisation" process, resulting in a "sneeze" when you unlock the portafilter (a sudden expansion of water/ steam. One of the things I disliked about my old Breville, was the wait between shots.

    Pressure relief has nothing to do with it.

    Edit: I bow realise this is pretty old thread (been a lot of that happening lately), but hopefully this is useful to someone
    Last edited by MrJack; 9 October 2016, 07:15 PM.

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    • #17
      What is happening, as happens on many small single boiler machines, is that the boiler retention valve leaks steam during the steaming process.

      The retention valve is a small silicone seal which is held under spring pressure onto the water outlet hole of the boiler. When making espresso, the pump pressure overcomes the spring pressure and water flows from the group head.
      When the pump is off, the silicone seal is meant to hold the water and steam in the boiler.

      Over time, this seal can perish or scale/debris can become stuck on the seal and the valve seat. When the boiler is under steam pressure, the steam can leak past the seal. This steam then forces its way into the puck and essentially makes it and the portafilter part of the boiler.

      When you remove the portafilter, you are pretty much opening the boiler and releasing all of the steam pressure. This is what sends the coffee flying and why it is so dry.

      To fix this, remove the shower screen and remove the retention valve screw using a wide flat head screwdriver. Clean the valve and then use a fine grade (1000-1500 grit) wet/dry sandpaper to lightly sand down the valve seat to make it smooth again. Wrap the sandpaper around a small flat head screwdriver or similar object and twist it around on the valve seat. You may need to repeat it several times to get it clean and smooth.
      Also descale the boiler in case there are scale flakes that make their way back onto the valve which would cause the same problem again.

      If you still have the problem after doing this, you will need to replace the silicone valve itself.

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      • #18
        Exploding Coffee - is this the valve?

        Thanks for the info - time to do some cleaning.

        Just wondering if this valve is the same as the one advertised as a Steam Valve on various places around the net ?
        Barista SIN 006 Steam Valve Repair 7pc. Kit



        Originally posted by noidle22 View Post
        What is happening, as happens on many small single boiler machines, is that the boiler retention valve leaks steam during the steaming process.

        The retention valve is a small silicone seal which is held under spring pressure onto the water outlet hole of the boiler. When making espresso, the pump pressure overcomes the spring pressure and water flows from the group head.
        When the pump is off, the silicone seal is meant to hold the water and steam in the boiler.

        Over time, this seal can perish or scale/debris can become stuck on the seal and the valve seat. When the boiler is under steam pressure, the steam can leak past the seal. This steam then forces its way into the puck and essentially makes it and the portafilter part of the boiler.

        When you remove the portafilter, you are pretty much opening the boiler and releasing all of the steam pressure. This is what sends the coffee flying and why it is so dry.

        To fix this, remove the shower screen and remove the retention valve screw using a wide flat head screwdriver. Clean the valve and then use a fine grade (1000-1500 grit) wet/dry sandpaper to lightly sand down the valve seat to make it smooth again. Wrap the sandpaper around a small flat head screwdriver or similar object and twist it around on the valve seat. You may need to repeat it several times to get it clean and smooth.
        Also descale the boiler in case there are scale flakes that make their way back onto the valve which would cause the same problem again.

        If you still have the problem after doing this, you will need to replace the silicone valve itself.

        Comment

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