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  • Diagnostic help needed for BFC Semi-Auto

    I have owned this machine for 5 years and has been totally reliable and I know it quite well as a member of the family. BFC Semi-Auto with 3 red rockers, absolutely great machine.

    My problem is.......
    Last week I noticed the manometer rising above its normal range of 1.0 to 1.2 .... to 1.6+ not regularly but once every now and then.
    I decided to do a descale as this was 8 months overdue even though mushroom was fairly clean. After the descale was complete I thought it time to check brew temp with thermocouple via group inspection hole.

    This revealed machine was running cool only hitting 88* at height of a pour...... Previously set to 93-94*
    After some time spent adjusting pressurestat (PS), machine would only hit 90* even when PS was wound in to operate between 1.5 and 1.7 ( way too high).
    Pressurestat is a Ma-ter XP700. I concluded that the initial problem was burnt and sticking contact points. These I took apart and cleaned ( quite sooty),after this the PS and contact points worked well and quiet,... BUT when set at the old PS range 1.0-1.2 temp was only 86*........ Winding it up to 1.5 again would only just hit 90*

    I now need a bit of advice as to where to next..... ! My thoughts now are to replace the Pressurestat as it may have a degraded diaphram !... BUT I'm not 100% sure this will cure the problem.

    Your thoughts and diagnostic skills would be appreciated.

    ***I should add that the relay on this pressurestat failed about a year ago , but with advice from one of our sponsors I was able to bypass, with no ill effects ( worn contact points maybe) but enjoyed the silent running without the loud CLICK of PS cutting in and out ........

    Cheers
    Greg

  • #2
    Separate issues.

    If it were mine I would replace the old pressurestat.

    If you were satisfied with how it made coffee before and have only become concerned because of the temperature check, then put the thermocouple away and enjoy the machine. Its a good model.

    Hope that helps.

    Comment


    • #3
      Thought I'd give this post a bump......

      Still waiting for those with the knowledge to offer an opinion, before I buy a new pressurestat.

      Cheers
      Greg

      Comment


      • #4
        While I have very little (none) first hand experience on the machine, I'm using some thermodynamics knowledge.
        You are able to achieve the correct boiler pressure ~1.1bar (a quick search shows that's close to the factory settings)
        So your boiler temp will be in the vicinity of 122'C

        If your brew water is dropping down to 86' you're dropping a significant amount of heat.
        that seems like a large drop in temp for an E61 machine, when the consensus seems to be that keeping it cool enough is usually the issue.

        how long of an ON time are we talking when these temps were measured? 30-40 minutes?

        If so, then the thermosyphon system may not be operating correctly (too slow??) and not heating the group properly so you're bleeding off too much heat in the brew water.

        My little dual boiler lelit drops 8 degrees from boiler to shower-head.
        I'd expect the E61 to be better than that.

        Or possibly a boiler under-filling issue. you're able to boil the water that's in the boiler and create the pressure,
        but there's not enough liquid in the HX to effectively transfer heat into the brew water.

        Just some ideas I can think of.
        Could be totally wrong, Chris or Charlie would have a better list of possibilities.

        Comment


        • #5
          Originally posted by hotshod View Post
          Thought I'd give this post a bump......

          Still waiting for those with the knowledge to offer an opinion, before I buy a new pressurestat.

          Cheers
          Greg
          G'day Greg...

          I guess that's fair enough mate but no-one in Oz knows more about these machines than TOK and any advice he offers comes from many years of experience and knowledge gained...

          Mal.

          Comment


          • #6
            Hello Greg,

            I'm with TOK and Mal. Pressurestat.

            Re temp, if you want an accurate indication of what your machine is doing, ditch the meat thermometer and use a Scace device. We have one and can do the work/testing.
            Last edited by TC; 14 September 2014, 07:33 AM.

            Comment


            • #7
              I have replaced the pressurestat ....... But temp is still down, not to the same degree but still low.

              To counter this I have increased pressurestat to cut in 1.1 and out at 1.3 ..... most of the time this is delivering about 89.5 to 91* measured at the inspection port after a 60min + warm up. Every now and then the group head will get quite hot with water dancing off the screen for 8-10 sec ( at these times I don't have a thermocouple in place so temp is unknown).This would happen once every 3-4 days after long idle period,2hrs+.

              So whilst machine is running better it is a mystery as to why I can't hit my old temp of 93-94*.

              Any ideas ?????

              Greg

              Comment


              • #8
                Originally posted by Robbks View Post
                You are able to achieve the correct boiler pressure ~1.1bar (a quick search shows that's close to the factory settings)

                how long of an ON time are we talking when these temps were measured? 30-40 minutes?

                If so, then the thermosyphon system may not be operating correctly (too slow??) and not heating the group properly so you're bleeding off too much heat in the brew water.
                *Yes I can easily run at 1.1 but that does not create enough temp.

                * Time wise it seems to make no difference 1 hour warm up or continually run for 4 hrs.

                *Just not sure about thermosyphon system of a Hx machine

                As for my thermocouple I regularly calibrate to local conditions .... so I know temp showing is very accurate.

                Your thoughts greatly appreciated.

                Greg

                Comment


                • #9
                  No joy after a couple of weeks fiddling with this machine.

                  The only way I know of to raise the brew temperature at the group head is to wind up the new pressurestat. So currently I have the pressurestat cutting in at 1.3 and out at 1.5 and this will idle at 88* and deliver about 93* at the height of the pour, .... but then take about 10min + to recover.

                  SO ..... are there any tricks you can used to add extra temp, other than cranking the pressurestat...?????

                  Greg

                  Comment


                  • #10
                    Think it's time to take your beloved machine to someone who knows them inside out mate...

                    Coffee_Machinist springs to mind...

                    Mal.

                    Comment


                    • #11
                      A philosophical discussion, because without having it on the bench in front of me, the discussion can only be based on the information you have given in this thread.

                      Firstly. A great machine,. I have a Splendor Maxi (V2) on my own kitchen bench.

                      If your machine was running at 93-94 degrees, then it must be assumed it is a V1 Splendor. Can you please let us have the first 4 digits of the serial number?

                      The V1 Splendor has shorter steam and hot water pipes that only move in a radial direction, and with a kind of ornate pattern punched into the drip tray.

                      The V2 (Maxi) Splendor has the longer ball jointed steam and hot water pipes that move in any direction and a drip tray with less ornate holes punched.

                      The performance of the V2 is significantly uprated from that of the V1......stronger steam delilvery, better thermal stability.

                      The V1 was an Italian spec machine and consequently ran at a higher brew temperature and required a hefty (similar to any other Italian spec machine of any brand) cooling flush.

                      The V2 is thermally adjusted internally to run at a more appropriate brewing temperature for the types of beans used in the Australian market. It runs at a lower brew temperature than the V1.

                      Your machine can be internally re-spec'd to run at a higher brew temperature by a knowledgeable service tech, if you wish. However that doesnt answer the question as to why you are seeing a different temperature range to previous...

                      Before doing anything like that, I would first consider the sentiment expressed in post #2 above very seriously:

                      "...If you were satisfied with how it made coffee before and have only become concerned because of the temperature check, then put the thermocouple away and enjoy the machine....."

                      Comment


                      • #12
                        Are you sure your pressure gauge is accurate? If it's not reading correctly then your adjustments would not be having the changes you expect.
                        Might be a silly idea but worth a try.

                        Comment


                        • #13
                          Thanks TOK for your lengthy and detailed response.

                          Unfortunately I think you might be confusing my BFC Semi-Auto machine with the Unico Splendor though I'm sure their internals would be very similar.
                          Quote.....
                          "Your machine can be internally re-spec'd to run at a higher brew temperature by a knowledgeable service tech, if you wish. " end quote.
                          Could you elaborate just how I could re-spec this machine to get the higher brew temp?

                          I do have another quick question that may help resolve this problem.....
                          This machine runs a vertical boiler. What level should the water be, when measured from the top of the boiler?
                          ( I'm thinking increasing this level could add to brew temp, rightly or wrongly...!! )

                          Cheers


                          Greg
                          Attached Files

                          Comment


                          • #14
                            Originally posted by hotshod View Post
                            Thanks TOK for your lengthy and detailed response.

                            Unfortunately I think you might be confusing my BFC Semi-Auto machine with the Unico Splendor though I'm sure their internals would be very similar.
                            Quote.....
                            "Your machine can be internally re-spec'd to run at a higher brew temperature by a knowledgeable service tech, if you wish. " end quote.
                            Could you elaborate just how I could re-spec this machine to get the higher brew temp?

                            I do have another quick question that may help resolve this problem.....
                            This machine runs a vertical boiler. What level should the water be, when measured from the top of the boiler?
                            ( I'm thinking increasing this level could add to brew temp, rightly or wrongly...!! )
                            Dunno how that happened.....Must've been having a brain spasm !

                            I am loathe to change a machine away from its standard spec (whatever that is) if it is working fine, and without being able to check the temp reading of this machine on a side by side test with another of known performance (or latest spec). Taking a temp reading without checking it with something else with the same instrument, at the same place in the temperature cycle, doesn't tell me much. And of course you say it was running at at a higher temperature previously, and the reason why hasn't been diagnosed. That would be the better way.

                            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.

                            If I were checking this on my own machine, I would start by removing and cleaning the probe first to make sure it is making a good connection, and then refitting it to the position noted above.

                            Then I say again, if the machine is making good coffee, put the thermocouple away....

                            EDIT: I always pull the plug out of the wall before I do anything with my machine...
                            Last edited by TOK; 14 October 2014, 12:38 PM.

                            Comment


                            • #15
                              Originally posted by TOK View Post
                              I find I get good performance from my machine by positioning the probe for the HIGH water level above the nylon insulator about say 10-15 mm.

                              If I were checking this on my own machine, I would start by removing and cleaning the probe first to make sure it is making a good connection, and then refitting it to the position noted above.


                              EDIT: I always pull the plug out of the wall before I do anything with my machine...
                              Edit, re plug out of the wall .... well noted and done !!!!

                              As for the water level the probe was all the way in, so I have done as you suggested removed and inspected, and it was as clean as a whistle and reset at 15mm above white nylon sleeve insulator.

                              This is one aspect of the machine I have never played with, so I hope you approve of my logic as to why it may influence brew temp.
                              On my last descale I checked water level via anti-vac hole.... it was 7.3cm below the top of the boiler. ( I thought that to be a lot of space for steam )

                              I shall now run it for 1-2 hrs and then check results.

                              BTW,... I'm fortunate to also have a VBM single boiler , while a bit tedious to use, but has been set up to run in a very narrow temp band, so it also delivers excellent extraction, and can provide a genuine comparison.

                              Cheers
                              Greg

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