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Diagnostic help needed for BFC Semi-Auto

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  • #16
    Originally posted by TOK View Post

    With regard to an effective boiler level:

    There are two probes on these models. The probe in the central position sets the LOW water level in the boiler, and the probe at the side sets the HIGH water level. I find I get good performance from my machine by positioning the probe for the HIGH water level above the nylon insulater about say 10-15 mm....
    Hi TOK

    I just thought I should point out to anyone else who is considering raising the water level within the boiler that on my particular machine the probes that set high and low levels were the opposite to what you described. With high level centrally mounted in the boiler and low level mounted beside it to the outer.

    I guess this could well be different on any make or model, so it's best to remove both probes just to be sure which one is actually the high level probe.

    Greg

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    • #17
      Problem Solved

      The initial problem I had with my BFC Semi-Auto was that it was running cool. Over a period from 1-4hrs idling the temp at the inspection port was anything from 73*- 86*and hardly ever hitting 90 at the top of the pour and then taking 15-20min to recover. This was despite adjusting pressurestat to hit 1.5, then replacing pressurestat and running high numbers and still no joy.
      This was not how a Heat-Exchanger machine should run...!!!


      Solved .......(All temps are measured via the inspection port.)
      By removing teflon restrictor plate/washer from brew/thermosyphon line. This told me the machine was capable of running hot,very hot,so I re installed restrictor about 4 times over a period of days while testing temps, each time I increased the hole size until I achieved a near perfect result.
      Restrictor diameter was 2.2mm at the end it was 3mm.
      The machine can now idle for 1-3 hrs and temp will be 90.5* to 92*.
      A 60 ml flush will deliver 93-94* at inspection port, pressurestat is wound down to kick in at .95 and out at 1.12+ and consequently the extraction process has vastly improved.
      This result makes me very pleased even though I wasted money on a new pressurestat.

      Happy to answer an questions after a 2 month journey to my problem.

      Cheers
      Greg

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      • #18
        Hi there.

        the factory spec for that orifice is in fact 3mm, and I expect the material has over time and perhaps through the effect of heat expanded, resulting in a reduced orifice size. Good to know that by your own experimentation, you have ended up back at the factory spec.

        For what its worth I dont think it was a waste of money to have replaced the pressurestat. Once they start doing what you explained in your first post, it becomes more frequent until you......replace the thermostat.
        Last edited by TOK; 29 October 2014, 12:33 AM.

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        • #19
          Would have been nice to get a mention for the time spent on the phone the other day helping you narrow down the problem to the restrictor. Could well have saved you a lot of time and money chasing the problem elsewhere. Just sayin'....

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          • #20
            Originally posted by coffee_machinist View Post
            Would have been nice to get a mention for the time spent on the phone the other day helping you narrow down the problem to the restrictor. Could well have saved you a lot of time and money chasing the problem elsewhere. Just sayin'....
            That was very poor form on my behalf, Rick "Coffee_Machinist" did in fact spend 10-15 minutes with me on the phone and directed me as to where I could find the damaged restrictor and spoke a lot of common sense about isolating the problem with my machine.
            I did send Rick a lengthy text message thanking him for his time and advice, plus outlining the results I achieved, and after 2 months of frustration I was very grateful.

            Post #17 Definitely should have made reference to the advice I received from Rick .....

            I would also suggest other CS members take a quick tour thru Ricks' website and check out his work with PIDs and other tasty restorations.

            The Coffee Machinist

            Greg

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