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Thread: VBM Super brew pressure problem?

  1. #1
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    VBM Super brew pressure problem?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    After attempting another descale of my VBM, I decided that I should let Renzo (Di Bartoli) fiddle with it, and it needed a service anyway, as it is 18 months old now.

    Before the service, when pulling a shot, the brew pressure gauge would start at around 2 bar, then stay there for about 4 or 5 seconds (pre-infusion, i presume), then build progressively to around 10 bar where it topped out, and at that point the pour would start to appear. The gauge held steady at 10 bar through to the end of the shot. This seemed normal to me.

    After getting it home this afternoon and letting it warm up, I pulled a couple of test shots on the serviced machine. Upon pulling the lever, the brew pressure gauge jumped immediately to around 8 bar, rising to 10 bar after around 8 seconds and holding for the rest of the shot, but it is wavering slightly, perhaps between 9.8 and 10.2 bar. The pour appears relatively normal, perhaps a bit thinner than it was before the service.

    The gauge shoots immediately to around 8 bar even if I pull the lever with no PF on the group to flush, which it never did before. Im concerned that there is something not right with the brew pressure or OPV.

    Any thoughts?

    Thanks,
    Mark

  2. #2
    Senior Member javabeen's Avatar
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    Re: VBM Super brew pressure problem?

    I dont think you have anything to worry about as I thought the gauge only displayed anything of use once full pressure had been established.

    The only thing that is a bit odd is when you say it wavers between 9.8 and 10.2 bar. If this is happening once the pour/drops have commenced, then it could indicate some scale in the OPV spring - maybe one of the site sponsors/more techo people can confirm this.

    Mine wavered a bit before I descaled last year, bounced more than wavered when it was at full pressure during the pour. But not in the range you stated..

    If its just scale then easy fixed...another descale :)

  3. #3
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    Re: VBM Super brew pressure problem?

    Wouldnt talking to/taking it back to Renzo be the pertinent thing to do? :-?

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    Re: VBM Super brew pressure problem?

    Sure, I will, but I thought Id just ask for some more expert opinions on here as well :)

  5. #5
    Senior Member javabeen's Avatar
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    Re: VBM Super brew pressure problem?

    Wheres the fun in that rf? ;D

    Then there would be no discussion...keep us informed Mark.

  6. #6
    Senior Member javabeen's Avatar
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    Re: VBM Super brew pressure problem?

    Any news Mark?

  7. #7
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    Re: VBM Super brew pressure problem?

    Hmmm - have run a few shots through now and its still acting differently. When the lever is pulled to start a shot, the needle jumps immediately to 9 bar, wobbles around this pressure for a while (for perhaps 8 secs or so, moving between 8.8 and 9.2 bar), then rises to a steady 10 bar final brew pressure.

    Advice from Di Bartoli is that all is fine, but a second opinion has suggested there may still be some residual scale in the OPV assembly. I was advised to unscrew the OPV and check for scale there.

    Who knows, perhaps the service descale has moved some around in the machine and it got stuck in the OPV? The story continues... :P

    Mark

  8. #8
    TC
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    Re: VBM Super brew pressure problem?

    Quote Originally Posted by 49481613240 link=1268731342/6#6 date=1268950265
    Hmmm - have run a few shots through now and its still acting differently. When the lever is pulled to start a shot, the needle jumps immediately to 9 bar, wobbles around this pressure for a while (for perhaps 8 secs or so, moving between 8.8 and 9.2 bar), then rises to a steady 10 bar final brew pressure.

    Advice from Di Bartoli is that all is fine, but a second opinion has suggested there may still be some residual scale in the OPV assembly. I was advised to unscrew the OPV and check for scale there.

    Who knows, perhaps the service descale has moved some around in the machine and it got stuck in the OPV? The story continues... *:P

    Mark
    Hi Mark,

    I think its worth testing with a p/f pressure gauge. This will show if there is something wrong with the gauge or if its an OPV or solenoid issue. There could even be partial blockage at the one way valve into the system pressure gauge.....

    Most importantly, how are the shots?

    For mine, I think CSers need to be looking at better filtration. Just because you have a drinking water filter, do not assume that you look after scale as well. In most cases you dont. Best bet is to chat with Bernard or Megan at Bombora supplies or your local sponsor...Its a couple of hundred very well spent...

    Chris

    Cheers

    Chris

  9. #9
    Sleep is overrated Thundergod's Avatar
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    Re: VBM Super brew pressure problem?

    Quote Originally Posted by 0B3E3334001C3039393A3A5F0 link=1268731342/7#7 date=1268952346
    For mine, I think CSers need to be looking at better filtration. Just because you have a drinking water filter, do not assume that you look after scale as well. In most cases you dont. Best bet is to chat with Bernard or Megan at Bombora supplies or your local sponsor...Its a couple of hundred very well spent...
    Agreed.
    If you noticed the mushroom on display at Di Bartoli, it came out of my Expobar during its first service after 2 years of only Brita filtered water.
    Renzo said it was too bad to try and clean and besides, it makes a good example of how bad things can get even when you think youre doing the right thing.

  10. #10
    Senior Member topshot's Avatar
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    Re: VBM Super brew pressure problem?

    Quote Originally Posted by 57626F685C406C65656666030 link=1268731342/7#7 date=1268952346
    For mine, I think CSers need to be looking at better filtration. Just because you have a drinking water filter, do not assume that you look after scale as well. In most cases you dont. Best bet is to chat with Bernard or Megan at Bombora supplies or your local sponsor...Its a couple of hundred very well spent...
    Quote Originally Posted by 576B766D676671646C67030 link=1268731342/8#8 date=1268958547
    Agreed.
    If you noticed the mushroom on display at Di Bartoli, it came out of my Expobar during its first service after 2 years of only Brita filtered water.
    Renzo said it was too bad to try and clean and besides, it makes a good example of how bad things can get even when you think youre doing the right thing. *
    Compared to the money you spend on a machine, a couple of hundred spent on a good fitration system with a scale reducing filter is very good insurance :)

    You also get the added advantage of filtered water for drinking and cooking as well :) :)

    Warren.

  11. #11
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    Re: VBM Super brew pressure problem?

    Update: Problem solved! (or is it just the symptom? :P)

    Unscrewed the OPV to find initially what I thought was a pile of white gunky scale on it, but turned out to be grease or lubricant of some sort. I removed some of the excess, not all of it, and screwed it back in as nothing else appeared to be wrong.

    Presto! the pressure gauge is acting like it used to, going to around 5-6 bar on lever pull, pausing, then rising progressively to 10 bar, then pour commences.

    I recall reading something somewhere that if you backed off the OPV to reduce the brew pressure a bit, its good to turn it slightly the other way again to seat the spring or valve correctly, perhaps this is what happened to me.

    It seems though, that the IT problem solving technique worked this time :)

    Mark

  12. #12
    Coffee+carbon=heaven Mono's Avatar
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    Re: VBM Super brew pressure problem?

    Good to see that all is good again :)

    Steve.



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