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Hello! Newbie here with some questions!!!

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  • #16
    Re: Hello! Newbie here with some questions!!!

    Originally posted by Intellidepth link=1218365375/0#14 date=1221445275
    Simonm: the explosions come from too fine a grind in a pressurised basket in a machine that doesnt have a 3-way valve. Commonly called "choking" the machine. (Ive worn a lot of coffee from my old pressurised machine. )
    "Explosions" are actually caused because there is no provision on low cost machines to bypass the pump pressure when it reaches a predetermined setpoint, in other words, an Over Pressure Valve (OPV) or Pressure Limiting Valve (PLV) - different names for essentially the same device.

    Ulka pumps (and their copies) are capable of developing pressures upward of 15 Bar (220+ PSI) within a closed circuit and considering that a lot of cheaper machines use Groups manufactured from various types of reinforced plastic, its not very surprising when the plastic lugs are unable to withstand the force being applied over an area of roughly 3 in2 which equates to something in excess of 650lbs.

    Thats why you should always start off with a coarser grind and work your way finer until such time as youre achieving good quality pours, NOT the other way around....

    Mal.

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    • #17
      Re: Hello! Newbie here with some questions!!!

      Oops Thanks Mal. Terminology stuff up - OPV not a 3-way!

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