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Heavily modded Silvia - brew issues

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  • Heavily modded Silvia - brew issues


    I have a heavily PID'd Silvia that has recently developed a severe brew+extraction issue that I haven't been able to solve.

    It started off a few months ago with the pump doing odd cycling (video here): 2012 09 03 09 15 36 - YouTube

    Now, the pump isn't oscilating like above, but all my shots spray like ol' faithful:

    This video best explains it:

    I've tried the following in multiple attempts to correct:

    1. Adjusted Grind size up and down (no affect)
    2. Adjusted Tamp preasure up and down (no affect)
    3. Tried different beans (no affect)
    4. De-Scaled with Citric Acid twice (no affect)
    5. Cleaned group head twice (no affect)

    I'm thinking maybe there's a pump-issue, but before I start ordering parts I thought I'd get some opinions...

    Many thanks!

  • #2
    Question: the modifications. Have you modified the pump power source at all?? The dropbox file has the pump cycling at the start and then it goes continuously. Since I know how my Silvia was wired, this implies you've hacked some kind of pre-infusion control regime into the pump.

    The spraying through - since the pressure does not seem to be going stupidly high I would put down to possibly distribution in the PF? Have you tried different techniques to make sure you don't have clumping whatever to stop the channelling? Do the pucks look channelled?

    I actually had a mini issue with my Silvia for a while with lots of channelling. I solved that by changing how I distributed the grinds. I have zero idea why it suddenly happened to me either. In so far as I could see I was still doing it the same as always, but when I carefully adjusted technique the problem went away...

    Just a thought.



    • #3
      The first thing I would do is disconnect all of the electronic stuff and see how it runs stock standard.


      • #4
        How old are the beans?, please clean your cup before making videos :0


        • #5
          In the first video it looks like the pump is cycling on and off with the PID controller. This could be caused by inadequate wiring: when the heater cycles on, it is creating a voltage drop in the circuit to the pump, temporarily stalling out the pump. When the heater cycles off the pump resumes.

          Perhaps the pump has been damaged by the time you get to the second video. Here you have pump cycling that is more irregular. Your alternate high pressure/low pressure cycles take turns compressing and releasing the puck, disrupting its structure. The severe channeling that you're getting has nothing to do with beans or grind size or the usual stuff, it's the pump's action that's ruining your puck's integrity.