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  • #16
    Re: New HX machine - boiler pressure too high?

    In all honesty,

    I dont think it is good advice to suggest that an owner of a new machine should start disassembling a machine while it may be still under warranty. While a Scace check and minimal adjustment remains in the province of "tuning" per se, disassembling components is a whole different kettle of fish and NOT to be recommended of someone without the requisite knowledge or at least equivalent mechanical knowledge....

    If the machine is still under warranty, such invasive incursions will no doubt void same.

    Mal.

    Comment


    • #17
      Re: New HX machine - boiler pressure too high?

      Originally posted by 775A5E525F330 link=1256380339/13#13 date=1260794606
      That is seriously slow going Geoff for a machine of this class. Should be capable of texturing this volume of milk in less than 15 seconds....
      to clarify - that was 250ml of cold milk that I did - about 400ml steamed.  I still think it could do better.  can a steam tip change help?  boiler pressure sits around 1.1-1.2 bar while steaming and never drops...

      Originally posted by 775A5E525F330 link=1256380339/13#13 date=1260794606
      This would be seriously worth doing and should enable any functional problems to be identified and fixed - Providing their Tech(s) know what theyre about of course...
      Ive arranged to take the machine there on Monday, so hopefully the scace testing will answer some questions for me

      Originally posted by 5F465052330 link=1256380339/14#14 date=1260795158
      You pass if all of the shots are within, say, a three second window.I suppose that the next question for you would be if the grinder is up to snuff.If thats the problem, your money would probably be much better spent towards fixing that.
      Thanks Luca.  I do certainly understand your point, and I do probably need to upspec my grinder (a better - probably doser - grinder should be on the cards soon), and fine tuning my dosing technique could certainly improve the taste of the coffee.

      Unfortunately, if my machine is running too hot now, none of those things are going to change that, and the quality of the end-product will still be lacking.  What Im hoping to achieve with the scace testing is to get my pressure set as best it can be, and to see what length of cooling flush is required to bring it back to optimum temp after idling for a while.

      I had a play tonight with the foam-cup and milk thermometer style temp measurement - not sure if I did it correctly - the pics should show if I did...  
      with the boiler pressure running 1.1-1.3, I let it warm up for about 35-40 minutes, then tested it with a cut-down foam cup over the shower screen.  the thermometer temp shot up to 98 deg and dropped to about 91 after about 25 seconds of flushing.  continuing for an extra 10 seconds or so, it stayed around 91 deg.  I let it sit idle for 5 minutes and repeated the process with the same results.  up to 98 deg, then down to 91 deg after 25 seconds.

      Then I upped the pressure to where it was before - 1.3-1.5 bar and got these results.
      30 seconds after starting the flush - still at 98 deg:



      55 seconds after starting the flush - down to 95:



      65 seconds after starting the flush - down to 90 deg and it didnt drop any further than that:



      Anyway I probably shouldnt get too carried away until its tested properly with the proper gear.

      Comment


      • #18
        Re: New HX machine - boiler pressure too high?

        Originally posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
        to clarify - that was 250ml of cold milk that I did - about 400ml steamed.  I still think it could do better.  can a steam tip change help?  boiler pressure sits around 1.1-1.2 bar while steaming and never drops...
        Yes, I was referring to a 250ml milk volume, not the volume of the jug being used....

        Originally posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
        Ive arranged to take the machine there on Monday, so hopefully the scace testing will answer some questions for me
        Excellent. Hopefully that will set your mind at rest with regard to the machines setup....

        Originally posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
        Then I upped the pressure to where it was before - 1.3-1.5 bar and got these results.
        Boiler pressure setting affects the Steaming Capacity more than that of the Group. I would raise the issue of the need for high flush volumes when you drop the machine in for its Scace test. It is possible that a thermosyphon restrictor (gicleur) has been omitted during the machines assembly at the factory and would be a simple measure for their Tech(s) to check it out while its sitting on the bench.

        Originally posted by 5A7676697C6B2F204A190 link=1256380339/16#16 date=1260965854
        Anyway I probably shouldnt get too carried away until its tested properly with the proper gear.
        Agree ....

        Mal.

        Comment


        • #19
          Re: New HX machine - boiler pressure too high?

          Hi Geoff,

          The behaviour of your machine sounds bizarre to say the least. I have only ever used the Mondiale once to train a client but I dont recall anything like that.

          I am surprised that there is no thermosiphon restriction employed, because I dont recall massive cooling flushes in the one I used. Id want to compare your machine with their demo model if I was you and all I can say is that if this is indicative of the machine in general, it points either to lousy QC, poor HX design or a lemon. If their techies reckon theres "nothing wrong" with the machine, one has to wonder if theyre all like yours??  

          My instinct is that thermosiphon restriction is employed in the Mondiale, but not installed in your machine or that you have defective restrictors or the wrong gicleur.

          The use of the scace will be really helpful..

          Things that you want to achieve:[*]circa 92-94 deg at the group, verified by the Scace[*]circa 9 bar at the group, verified by porta-filter pressure gauge or Scace II[*]approx 1.2 bar at the boiler, whilst maintaining the above.

          I am pretty sure, that I can suggest some fixes over the phone which will get you near enough. I can also advise on how to check if a restrictor is installed in your machine as well as the gicleur.

          The thermostability upgrade we developed with Prof. Pete on the Giotto Premium allows for better settings than those above-  which is how we were able to soup it up. Nevertheless, if you can lock into something close to my suggested settings, you will have a much happier machine.

          regards

          Chris

          Comment


          • #20
            Re: New HX machine - boiler pressure too high?

            I would be a bit wary of your measuring device, those milk thermometers are not super accurate.

            Comment


            • #21
              Re: New HX machine - boiler pressure too high?

              Originally posted by 323C313E293F3E500 link=1256380339/19#19 date=1261170478
              I would be a bit wary of your measuring device, those milk thermometers are not super accurate.
              On that point, stick it in a pan of simmering water and check it out. It should of course read 100°C adjusted for your barometric pressure.

              If its accurate, Id say the machine is running hot, but somehow only when idling :-?. This will need someone who is familiar with the innards.

              Greg

              Comment


              • #22
                Re: New HX machine - boiler pressure too high?

                Originally posted by 7B757877607677190 link=1256380339/19#19 date=1261170478
                I would be a bit wary of your measuring device, those milk thermometers are not super accurate.
                yeah - I understand that even if the thermometer is reading correctly, its not the most scientific way of testing the temperature.
                I verified that the thermometer accurate at 100*C by putting it in a saucepan of water boiling on the stove, but the accuracy below that temp hasnt been tested - I was really just playing trying to get some idea where its at because I was getting impatient having to wait until Monday to test it properly. Ill have a better idea of the real temp then.

                Comment


                • #23
                  Re: New HX machine - boiler pressure too high?

                  Excellent, I have just had a couple of examples of when people have been using "recently calibrated" thermometers which were out by 15 degrees. Didnt make for great coffee.

                  Comment


                  • #24
                    Re: New HX machine - boiler pressure too high?

                    Hi Cooper,

                    Curious to know how you went with your hot running Mondiale....Any success in settling it down?

                    regards

                    Chris

                    Comment


                    • #25
                      Re: New HX machine - boiler pressure too high?

                      Originally posted by 02373A3D09153930303333560 link=1256380339/23#23 date=1262857453
                      Hi Cooper,

                      Curious to know how you went with your hot running Mondiale....Any success in settling it down?

                      regards

                      Chris
                      Gday Chris
                      jurys still out im afraid.  Im thinking of getting one of Erics TC devices sent over from the US so I can keep a closer eye on it.
                      After installing a restrictor ~2.8mm I thought it was fixed, but in reality I think it just takes much longer to warm up.   If I wait half hour to 45 mins after turning on, it barely needs a flush.  after a couple of hours idling, it seems to need just as much flushing as it did before I installed the restrictor.  then after flushing it doesnt heat back up quite as quickly as it used to, but it still needs a bit of a flush between shots (Im not very quick but that time also includes steaming the milk for the first shots).  

                      As it stands, the flushing does seem to be reduced overall, and with a way to monitor the temperature Ill probably be quite happy with it how it is.  Erics TC seems to be the neatest option for doing that from what Ive found so far...

                      maybe if I install a restrictor with a smaller orifice (2mm or 2.5mm??) it might maintain temperature better once fully warmed up, but could that mean it will be taking up to an hour after turning on before I can start making coffee??

                      due to the long warm up times, the machine is usually on all the time except for while Im at work or asleep - turns on by a timer about 45mins before I get up in the morning...  Do most people leave machines running all the time like this or turn them off when not in use?  I only use it a few times a day, but dont like the idea of waiting an hour after I get the urge for a coffee...

                      Im getting good tasting results out of it lately anyway which is great.  My wife has noticed an improvement since I modified it, which is good since she was a bit concerned when it was all apart on the kitchen bench that it might never work properly again.  no faith in me  :

                      one other thing - after installing the restrictor the machine seems to sound different. It makes sense to me that the restrictor would increase load on the pump - is this likely to be a problem??

                      oh and in case you or anyone else wonders what the Cooper69S is all about, when I originally joined the forum, my toy was a 1969 Mini Cooper S.  Awesome car, should never have sold it but thats another story.  One day Ill change my username so that I stop reminding myself about it...

                      thanks for the assistance in choosing a better grinder, hopefully it will turn up here in the next few days

                      Geoff

                      Comment


                      • #26
                        Re: New HX machine - boiler pressure too high?

                        Hi Geoff,

                        2.8 is big- you may get better results out of 2 or 2.5....You really do need to play with a Scace to see what its up to. You may also need to experiment with pressurestat settings and different gicleurs as well.

                        I have been using my Scace with Andys roast monitor software. Real time curves!  8-) [smiley=thumbup.gif]

                        The heat up is concerning though.... :-/

                        I have very little experience with this machine but it really sounds like it could be a case of dumb HX design to me. If the HX is too fat and too short, doesnt matter a whole heap what you do...

                        Sadly, its pretty much impossible to create smart design from dumb

                        Chris

                        Comment


                        • #27
                          Re: New HX machine - boiler pressure too high?

                          Could even come back to Boiler Water Level or HX Mixing too.... :-?

                          If this is not right it will alter the characteristics of the actual Heat Exchange to the Brew Water, to the extent that it wont matter what you do any where else in the hydraulic circuit ultimately the Brew Water is going to reach the same temperature as always (give or take) and require the same volume of a cooling flush.

                          Personally, Id take it to someone like Chris who has all the test gear on hand combined with the knowledge gathered over many years to properly assess what is going on. It is really very difficult to try and determine the root cause of this sort of a problem via remote control unfortunately....

                          Dont know if any other sand-groper CSers can recommend someone to you....

                          Mal.

                          Comment


                          • #28
                            Re: New HX machine - boiler pressure too high?

                            Hadnt noticed this thread before due to being away ...

                            Ive had a Mondiale for a couple of years and now getting what
                            I think are very good results from it.

                            At first though I did think it was running a bit hot and giving a
                            longer cooling flush than expected. It was also adjusted to an
                            excessively high brew pressure (13+ on the gauge).

                            But since a couple of adjustments its working well. First was
                            pressurestat, adjusted down to a 1.1 - 1.3 range. Then the
                            brew pressure. It took a while to get around to doing this as
                            it required pulling the cover off, but turned out to be
                            pretty straightforward (I posted about that a few months ago).
                            That is now set to just over 10 on the gauge.

                            With this, cooling flush is 10 - 12 seconds when hot, and very
                            short pulling consecutive shots (which I dont do very often so
                            havent measured it). Warmup time is about 45 minutes but
                            could I think get away with less.

                            The technicians in the workshop of the Isomac distributor gave
                            helpful advice on a couple of occasions about the workings of
                            the machine and what I could expect to find when adjusting
                            the OPV. Saved me a fair bit of fiddling around.

                            I did for a while consider looking into restrictor mods etc but
                            reached the conclusion that such mods can affect other aspects
                            of thermosyphon operation and without knowing more about its
                            specific design possibly difficult to get right.

                            Nonetheless I think the evidence is a bit thin to categorize it as a
                            dumb HX design ... Would be interesting to run some tests though.

                            FWIW a while ago I attempted some temp measurements by poking a
                            calibrated TC lead into a group handle stuffed with foil and locked
                            into the machine (this can damage the TC wire but I took the risk).
                            IIRC this stabilized in the 91 to 93C region after the flush.

                            Anyway Im now pulling shots in the 30 second range with good
                            crema and most importantly showing the origin characteristics
                            that Id been hoping for, and consistent with what I get cupping
                            the same beans.


                            Comment


                            • #29
                              Re: New HX machine - boiler pressure too high?

                              this is very interesting...
                              I arrived at the conclusion that my machine was behaving as it was designed to, based largely on it seeming to have the same temperature characteristics as many HX machines in the USA that Ive read about on the HB forums. Considering that many of the machines that are talked about on here as behaving very nicely are apparently modified on request by certain Australian distributors, Ive assumed that mine is an unmodified machine and I need to tweak it so that it plays nice...

                              I found another thread a while ago from another Mondiale owner who seemed rapt with his machine, so sent a PM but he doesnt appear to have been active on the forum for a while and I havent heard back... other than that Ive been able to find out very little about other peoples Mondiales.

                              dumb HX design is something that would be pretty difficult to fix, but now Im thinking that if other Mondiales only require a 10 second cooling flush when hot, then why is mine different?? The scace test seemed to verify that with the boiler pressure at 1.1-1.3 bar, my machine was running 94-95C after about 30 to 35 seconds flush and seemed to stabilise on that temperature.
                              now after installing a (slightly big) restrictor it seems a lot better, but if other people are finding that their unmodified machines are behaving better than mine, maybe something is still amiss??

                              Originally posted by 28213A2225212E400 link=1256380339/27#27 date=1263016886
                              I did for a while consider looking into restrictor mods etc but
                              reached the conclusion that such mods can affect other aspects
                              of thermosyphon operation and without knowing more about its
                              specific design possibly difficult to get right.
                              Hazbean do you know if your machine has any restrictor installed?
                              also how do you find the steaming performance? from some of the numbers I mentioned above, Im told mines a tad slow.

                              Originally posted by 04292D212C400 link=1256380339/26#26 date=1262868481
                              Could even come back to Boiler Water Level
                              this isnt something Ive considered before... how might it affect things??
                              thanks

                              Geoff

                              Comment


                              • #30
                                Re: New HX machine - boiler pressure too high?

                                Originally posted by 5164696E5A466A63636060050 link=1256380339/25#25 date=1262861353
                                If the HX is too fat and too short
                                here it is
                                In...


                                where the restrictor has been installed... size of the hole in the fitting at the end of the pipe was 8mm, and as I mentioned above, it now contains a restrictor at about 2.8mm


                                Out...


                                Out again...


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