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Faema E98 brew pressure and gicleur

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  • Faema E98 brew pressure and gicleur

    Hi All

    So I'm using the plug under the group (about 1/2" allen socket one) for the location of the gauge to set my OVP/brew pressure regulator (vibro pump). NOw, do I set it to 9 bar with a blind basket (giving about 4-5 bar during an extraction, or wind it way up to get 8-9 bar during an extraction?

    Also I need a very very fine grind to get required extraction times with a pool of water on the puck, and have discovered my gicleur/injector whatever is 1.25mm, and I believe the machine should have a 0.8mm one? I think the injector on the water fill solenoid might still be a 0.8 so might try to swap them? (parts listing shows the same part number for both, but my machine has been played around with by the previous owner -shitty restaurant- to whack out coffees in the shortest possible time). Even the OVP was jammed closed when I got it!!

    Ramp up time is always 4-7 sec.

    Thanks

  • #2
    Ideally you would measure the pressure in the group with a portafilter mounted gauge and set that to 10 bar. That should roughly translate to 9 bar during extraction.

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    • #3
      If you only getting 4-5 barg at the pump during extraction, but 9 barg with the blind, then my first thought is that you have a puck problem (followed by a pump/supply problem). Put simply, there is not enough resistance across the puck to increase backpressure at the pump to 9 barg.

      This could be any/all of:
      - dose too low
      - grind too coarse
      - underroasted coffee
      - stale coffee
      - puck "damage"


      Was the machine plumbed in previously?
      Last edited by MrJack; 26 May 2016, 01:25 PM.

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      • #4
        Tried all sorts of diff beans, grind is generally finer than most other people. Pool of water on puck after extraction, temp of about 96degc of water flow when machine nicely warmed up. Machine takes water from it's own reservoir, which is plumbed in , yes.
        So I should set the blind filter pressure to 10? I should have 8-9 bar DURING EXTRACTION right?

        I found the 0.8mm gicleur in the water inlet line, will swap and see what happens.

        I work in a coffee cart on occasion, but purely am an amateur.

        Comment


        • #5
          A gicular in the inlet line to the pump? I don't know if that is common in espresso machines, but its a terrible idea from a pump operability point of view. Pump system design typically aims to minimise pressure drop on the inlet...

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          • #6
            It's an E98 A1 - the high pressure inlet from the tap (modified by the 0.8mm jet) fills up the reservoir which is then sucked up by the vibro pump. If you had no injector on the water inlet you'd blast the contents of the reservoir everywhere.

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            • #7
              The A1 is a rotary pump. It sucks straight from the tank. From memory there is a restrictive disc in the line feeding the group, as well as a metal gauze disc.

              Cheers

              Comment


              • #8
                Originally posted by floatingkiwi View Post
                It's an E98 A1 - the high pressure inlet from the tap (modified by the 0.8mm jet) fills up the reservoir which is then sucked up by the vibro pump. If you had no injector on the water inlet you'd blast the contents of the reservoir everywhere.
                Thats alright then
                So from a hydraulic perspective, it being plumbed in is irrelevant (and the restrictor in the tank inlet line has no influence on what happens during extraction).

                Comment


                • #9
                  I just noticed the OP mentions a vibe pump so my comment might not apply to his machine.

                  For the A1, when plumbed in the machine still draws water out of the tank. It just tops up the tank if it gets low by opening a solenoid that the mains water is connected to.

                  Cheers

                  Comment


                  • #10
                    Originally posted by artman View Post
                    The A1 is a rotary pump. It sucks straight from the tank. From memory there is a restrictive disc in the line feeding the group, as well as a metal gauze disc.

                    Cheers
                    Correct, that is the injector/gicleur whatever you want to call it and restricts the pump flow to the group. I have a vibro pump so only 1 injector in the system (apart from the water reservoir inlet). The rotary pump versions also have one in the hot water dispenser line, i.e 3 in total including the water feed to the inbuilt reservoir.

                    Comment


                    • #11
                      Originally posted by MrJack View Post
                      Thats alright then
                      So from a hydraulic perspective, it being plumbed in is irrelevant (and the restrictor in the tank inlet line has no influence on what happens during extraction).
                      Yes, but as mentioned there is also the injector (now back to 0.8mm from 1.25mm) in the brew supply line that I'm playing with. Frankly the 0.8mm injector seems to be the same as the 1.25mm. I haven't noticed any difference.

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                      • #12
                        Having a larger restriction wouldn't explain the additional pressure drop anyway. I gather most people experience 0.5 -1 bar pressure drop, so your observation of 4-5 bar flowing pressure drop suggests a different root cause.

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                        • #13
                          So I should actually have a 9 bar pressure at the group DURING an extraction?

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                          • #14
                            Or there abouts, yes.

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                            • #15
                              crikey my vibro pump must be knackered then - I can easily get around 12 bar with a blind basket but only about 4-6 bar during an extraction of 60ml in about 28 secondsish. Or something else is wrong.....

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