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Thread: Should a vibration pump pressure be set higher than a rotary pump?

  1. #1
    Senior Member NakiChap's Avatar
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    Should a vibration pump pressure be set higher than a rotary pump?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have been told that a 12 bar factory setting on a machine with a vibration is correct and should be left at that setting is this true ? :-?

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    An interesting question :)

    Technical monosyllabic answers of either YES or NO, would have to be complicated by all of the following:

    Many manufacturers have, and some still do, set the pump bypass pressure to somewhere around 12 bars.

    I dont know why, but they do.

    Do the machines work?

    Yes.

    Can the machines be improved by lowering the pump pressure to within the figues specified in the specification for what constitutes a proper espresso?*

    Sometimes.

    Depends on whos wants to do this, what he has been reading, how much he believes, and the* miriad of variables involved in making a good coffee.

    ie someone that doesnt have a good handle on making espresso (and there are plenty) would be clutching at straws to lower a 12 bar pump pressure to 10, expecting to see a significant improvement in their coffee, if they are not properly handling, and have a good understanding all the other vatriables involved.

    So.....if you were on top of your coffee making, lowering the pump pressure on whatever your machine is, may give you a noticeable (to you) difference, possibly a good one.

    Otherwise.....if you are happy bwith your machine and what it is doing for you with your current coffee making capabilty, it may not make much difference (to you).

    There are an aweful lot of people in these forums, drinking specifications , brand names and labels. If you blind folded them and did a one on one comparison between a machine set to 12 bar, and an identical machine set to 10 bars......they may or may not pick any differences and if they did, could they pin them on only the effect of the difference in pump pressure?

    Reading all this stuff on the www, opening up all the opportunities for difference, only seems to complicate matters for some.

    Only you will know if you try.

    To complicate all the above,* some machines dont have a means to adjust the pump bypass pressure from the factory set point, and if they work, they just work!

    Hope that helps.

    Attilio aka Billy Big Potatoes* ;)
    Coffee and Coffee Equipment Psychologist, and
    very first CS site sponsor.

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    Senior Member NakiChap's Avatar
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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Thanks Attilio :) yes your respond has helped

    I notice a big difference with my espresso pour and flavour when I adjust the brew pressure preffering to have my machine set at around 10.2 bar for me

    I just was a bit confused as I had a technician look at my machine and when it was returned to me he had adjusted the brew pressure back to 12 bar stating that is the correct setting for this model with a vibration pump,

    Cheers
    MNSTA

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Some of the early Breville Dual Boilers, that have a vibe pump, came out of the factory set at 12 bars. The Breville experts say they should be at 10 and they have been resetting them free of charge.

    Vibration Pumps vs. Rotary Vane/Permanent Displacement Pumps.

    It is common here at CoffeeSnobs for rotary pumps to be considered as being superior to vibe pumps.

    The following is from 1st-line Equipment, LLC, for what it is worth.

    ďA common myth for newcomers to the espresso machine world is that rotary vane pumps, also known as permanent displacement pumps, are superior to vibration pumps.Ē

    http://www.1st-line.com/cofffact/vibration-vs-rotary.htm

    Barry.

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Yes Barry...." a common myth".

    In terms of factory set pressure settings.......you cant discount that some manufacturers have simply reset their production line pump pressures down from 12 to 10, because its the easiest way to deal with ever growing client expectations through extensive web based discussion on what is "academically correct".

    Well set up ("good) machines that were set to 12 bars always made good coffee regardless (notwithstanding that the coffee may be improved by modfying the set pressure down).

    Clients these days walk into a showroom with a list of specs tightly clenched under their arm, and if any of the equipment doest stack up to the specs, it is quickly discarded as a contender.

    Far easier for manufacturers to adjust themselves for what the market is dictating than to try and argue and lose market share...while someone else will be picking it up behind them* ;)

    There is always more to all this stuff than meets the eye at first from an end user point of view.

    With regard to the diff between vibe/solenoid and rotary pumps:

    Simply put, the difference lies in the capability of the different type pumps for volumetric delivery.

    EG:

    A vibe pump in a 1 group machine = no worries.

    A vibe pump in a multi group machine = cant deliver the volume if you have more than 1 group operating at the same time ( or the boiler auto fill).

    A rotary pump in a multi group machne = no worries.

    Whats the real difference then? Ability to pump volume in multi group machines.

    Vibe pump machines can be and are in various circumstances, hooked up for mains water operation but again (in my experience), only in single group form

    And.....

    If you built*a multi boiler machine that had an individual vibe pump for each group as well as the auto fill, it would operate as well as a machine with a rotary pump.

    Or....

    If someone built a vibe pump that was physically larger than the current type, it would pump more volume.......*


    But of course the fact is, why bother with all the extra design and build, when a rotary pump can already do the job?


    What is he only other real difference that I can see then?* Smoothness and noise level during operation of the pump.

    The rest, is nothing more than web based myth, very often perpetuated in sales pitches to get clients to buy one machine over another.

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    TC
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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Yes- agreed as to the myths.

    You buy a rotary pump because you want to plumb in and/or for the noise factor. The rest is mere placebo effect.

    Chris

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Yeah and on this occasion I would have to say that my immediate past post on the difference between the pumps could very well be worthy of being turned into a "sticky" by the mods, and oops on another note it seems apologies may be in order as I forgot to sign off properly. Here it is:

    Attilio
    Billy Big Potatoes ;) and
    very first CS site sponsor.

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Quote Originally Posted by 132730263D0A163A33333030550 link=1338472554/6#6 date=1338613873
    Attilio
    Billy Big Potatoes and
    very first CS site sponsor.
    Always preoccupied with the size of his spuds ::) ;D

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Thanks Attilio and Chris for your expert advice on the vibe v rotary pump myths.

    I have a Breville Bes 900, Dual Boiler. Breville came under criticism here from Snobs when they first disclosed that their new Dual Boiler machine would have a vibe pump.

    From the discussion here and the 1st-line Equipment website, perhaps Breville made the right choice in using a vibe pump on their single group domestic machine, pumping from a tank.

    I understand that a vibe pump has the advantages of smaller size and lower initial and replacement costs.

    My Bes 900 has the O P valve set at 12 bar. I can drop the pressure to 10 while brewing by slightly opening the hot water valve. I* donít notice any difference in the coffee.

    Barry.

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Hi guys
    interesting post. I have a 3 group linea at my cafe, serviced this week by a very reputable company. Their tech set the pump pressure at 10 bar, I assume to accommodate for three groups running at once. It still didnt make sense to me, so after discussions with my coffee supplier (also highly reputable) pump pressure was adjusted to between 8-9. Personally I noticed a better extraction.
    I then came back to my awesome expobar minore 3, to see the pump hammering away at 12 bar.
    Whats better here? Im considering dropping it down considerably assuming that it can be done....any thoughts on whether I should or shouldnt?

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Presumably your tech adjusted the pump to 8-9 bar (or whatever) while all three groups were brewing coffee. Which means if only one group was brewing coffee and the other two were idle, you would note a slightly higher pressure reading on the gauge.....OR, he set it to 8-9 bar with one group brewing and the others idle.* Which means with all groups operating the pressure reading on the gauge will be less......You cant have it the same all the way through.

    With respect to your Minore. A very wise old coffee roaster once said to me (as a result of my asking him a technical question about coffee roasting)....."you try".

    I have since lived by that advice over the course of many many years.

    Regardless of whether afterwards you think you notice a better extraction, the question for me remains, will that mean the original extraction was not good, or have you simply improved on an already good extraction?

    This is the trouble with all this academic mumbo jumbo that goes on in these sites. Readers with no experience take it all on board and make judgments about what is "correct" and what is apparently "not correct" (or wrong) and then place demands on their equipment and their suppliers.* When a lot of it is actually "all good" and there are lots of interpretations out there....If something is different that doesnt make it wrong even if it may respond to a bit of tuning. And after the tuning, many clients cant tell the difference while others can.

    Billy Big Potatoes.

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    Senior Member NakiChap's Avatar
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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Quote Originally Posted by 404B5E50445E4B442A0 link=1338472554/9#9 date=1340523449
    I then came back to my awesome expobar minore 3, to see the pump hammering away at 12 bar.Whats better here? Im considering dropping it down considerably assuming that it can be done....any thoughts on whether I should or shouldnt?
    You can adjust the pump bypass pressure from behind your drip tray, just remove it and you will see a hole with a flat head type screw,By memory I think I turned mine about one and a half turns anti clockwise to get it down from 12 bar I have mine reading 10.2ish with the blind filter in.

    No harm in trying see how you go.

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    Re: Should a vibration pump pressure be set higher than a rotary pump?

    Behmor Brazen - $249 - Free Freight
    Thanks guys - respect to your big potatoes ;)
    Thanks MNSTA. Good advice - I will try it and let you know



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