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  • New To this site, new to machines

    Hey guys, new guy coming into the pointy end Just had a question regarding advice on a rebuild. Last year I picked up coffee machine restoration as a side hobby to keep my sanity while grinding through schools monotiny.

    Heres where I had questions. I recently picked up a La Cimbali M20 for a cheap price i believe and am doing a full rebuild of it (will post pictures when finished). Started with a complete disassemble and acid dipping (citric of course) and everything is going well. Currently waiting on gaskets and such to come in so i can reassemble. While waiting, I usually crawl along craigslist for good finds and stumbled upon another M20, this time it was a dosatron ;D. Perfect because I figured now I can keep the dosatron and sell the other. However when I picked it up, I saw that this one was in worse condition than the other one. So now, I figure ill take the best of both and build a frankenmonster and then rebuild the other and put back on craigslist for somebody else to enjoy. I was assured both were working perfectly before being pulled and looking at both, theyre built like tanks; theyll work :].

    Although I do have a request for advice from more experienced people here. I believe one of them was built before the other since the groupheads are different. One has a direct feed from the supply into the HX, while the other has an additional "cooling" pipe. Knowing the importance of temp. stability of groups, which configuration is better? I have two pictures attached to this to help clarify.

    As you can see, the first picture has a pipe going around the solenoid while the other doesnt. Any ideas as to which is better and why?

    Thanks for all the help!

  • #2
    Re: New To this site, new to machines

    Also on second note, newbie question, can somebody explain the two different dose buttons on the machine. One has the cups half full and the other has them full. I always thought it was either a one or a two shot dose dispense. :-/


    • #3
      Re: New To this site, new to machines

      half-shot single, full-shot single, half-shot double, full-shot double? (basically four extraction times) afaik

      Also, looking at the pics, Id say the group in the top pic has better thermal stability in the group compared with the second pic, but then, Im not a technician, and have no experience with these machines.

      Have fun and keep us updated! (love pics)


      • #4
        Re: New To this site, new to machines

        I would say the buttons are just different pour volumes that you can program if you dont want to start/stop manually.

        Interestingly, my Faema machine has the same group design, it has the casting as per the first pic (with the additional water loop), but the pipes are as per the second pic.

        Not sure how it would be different thermally wise, these pipes only flow water during brewing, they finally go via the tube submerged in the HE beofre flowing out of the group. The spaghetti stuff is all prior to this.



        • #5
          Re: New To this site, new to machines

          Anyone familiar with these machines need a specific picture taken?

          This is sort of a shameless post as I need a total of 5 posts before I can post an update on the restoration process that has linked pictures from my photo dumping provider.


          • #6
            Re: New To this site, new to machines

            Actually, I do have a question, I am curious as to how much this machines original price was? I have another smaller machine which is a Grindmaster Espressimo 1750 which is much smaller and much simpler in design that I see being sold online for 5-6k so it just makes me wonder as to the original asking price of this guy.


            • #7
              Re: New To this site, new to machines

              Welp, got my 5 posts, so its time to dump pictures.

              Let me update on the status. Originally I was planning on completely rebuilding both before i come back to post, but I think itll be better if i document as I go.

              Hopefully the pictures show up as I intend, otherwise it will be difficult. This is what I started with. Completely basic M20 that had only manual on / off switch for each group. It was in clean condition to begin with but I decided to clean it none the less. Which was a good idea because the boiler had a layer of hardwater on it that I tried my best to remove. It did mostly come off but i dont have the reach to really scrub the inside as only one side comes off.

              side shot after having a panel off to remove the boiler and float. You can see my crafty method of draining the boiler into a pot (it was full). For anyone that considers buying one of these used. They are heavy! Make sure to drain the boiler before you try to move it. Lesson learned from my end.

              Full 10L boiler. It is rather an impressive thing. I wish i had a scale next to it.

              All the panels removed and ready to disassemble slowly now. For anyone attempting to restore one of these, if youre not so mechanically inclined, take lots and lots of pictures. It will save you later when you are trying to put everything back together.

              Front of the machine with the group heads and piping.

              Trusty helper that likes to bat screws and nuts under the couch then walk away as if she didnt do anything.

              One just has to appreciate how nicely these things are built. They are simple, but wonderfully laid out and very easy to work on. Practically speaking.

              Electrical system for the manual version is simple. On off switch, on off relay, and two group switches. I made sure to take lots of pictures of them with labels so I know how to hook it up later. Mechanical Engineer here, pipes, motors and machinery is no problem for me. But put some wires and terminals in front of me and I lose my intuition. Really, especially since youre dealing with 220V, make sure you label and put back things together how they originally were because things could get dangerous. Also it doesnt help that the M20 manual is really hard to find. I still havent found one for my machine but only for the Cimbali Junior version of this.

              both group pipeworks. Next is removal of groups and the HX

              One down, one more to go.

              Years of no cleaning and back flushing. Gross


              So far the first machine is completely disassembled and acid dipped. I had a really hard time removing the feed pipe on one of the groups because a fitting had welded itself on the group from hard water deposits. I ruinied the fitting in trying to remove it and it turned into a real big pain in the butt. Here you can see just how mangled it got by the end.

              I ended up taking it to my machine shop and had a good friend mill the guy out just until the teeth of the fitting showed up. THen we collapsed it and pulled it out. But again, got very lucky that I have access to a machine shop and a shop adviser that has such immense knowledge to remove fittings without damaging the actual threads.

              Theres the fitting removed and after the acid wash. New pipes came in from local distributor. Wonderful quality.

              Notice the new copper shimmer.

              Well, now I have to go back to work. Will update later in the week when new gaskets and such come in. Ive finished cleaning the first m20 and painted the frame with epoxy paint so its still clean, but have other misc parts that I have to sand down again and repaint as rust damage has made the paint peel off. Assembly should go quickly but my updates will slow down due to work.

              Before I leave, I have decided to keep the groups with cooling pipes for the new build. I think this is a better design to minimize cooling flushes before pulling shots. That and I believe those pipes were added for a reason later on so I dont see why I should stick with an older design.

              And without further stalling, and since were all coffee snobs here. Here is the best example of why you should descale and clean your coffee machines periodically and thoroughly! This is inside the heat exchanger where fresh enters and ultimately ends up in your coffee.

              Those are some sort of deposits that look absolutely horrifying.

              Till next time


              • #8
                Re: New To this site, new to machines

                Originally posted by 796064656C7461627B0D0 link=1322436141/5#5 date=1322593829
                I am curious as to how much this machines original price was?
                I dont know the original price exactly but it was certainly well above $3k. ;D

                Java "Hence the move!" phile
                Toys! I must have new toys!!!


                • #9
                  Re: New To this site, new to machines

                  Originally posted by 2A3337363F273231285E0 link=1322436141/6#6 date=1322594717
                  Originally I was planning on completely rebuilding both before i come back to post, but I think itll be better if i document as I go.

                  Looking good so far.


                  • #10
                    Re: New To this site, new to machines

                    Small update.  Been taking apart the other machine and noticed that it is a total disaster.  It is either a much older machine or the previous owner did not take care of it at all and just used it without performing its routine maintenance.

                    This is what I started with.  Basic M20 Dosatron version.

                    All the top panels were removed to put in my cars trunk when transporting.  Its all there so no worries about that.  However, the insides were very filthy and a lot of hard water stains.  Im worried about the boiler right now because it showed signs of leaks near the heat exchanger welds.

                    In fact, the previous post I posted a picture of the inside of one of the HXs. 

                    I threw them into a pot of concentrated dish washer and let them simmer on the stove in hopes of removing all the old coffee deposits from the heads and the exhaust pipes.

                    It was actually very effective.  There were some remains but I will worry about them later after I pull them tomorrow from the acid bath.

                    Heres some pictures from the rest of the disassembly.

                    Sadly, I was under the impression that this was working, but as I was taking it apart, I found out it was not.  The pump had seized.

                    It is badly rusted over and Im not sure I am even going to bother trying to clean it.  The motor seems to be functional.  It turns over without any resistance but the pump is toast.  What is interesting is that it is a bigger pump than the other M20 that I have.  This one is rated up to 250 psi and I think it is the 125 gallon / hour model.  The other is the 175 PSI.  Im thinking that due to the additional piping and flow meter restrictions, it needs a little more umph.  But I may be wrong.  Ill be using another pump i have into the new build that is equivalent to this one and see how it works. 

                    Another speed bump along the road was the condition of the boiler.  Everything had water damage to it.  The bolts were rusted on and the group gasket was hardened.  Although I did manage to take it appart, I broke one of the threaded rods that tightened the boiler cap.  Will need to buy some new parts for that.   Heres some pictures of the goodies inside.

                    Im letting the parts soak in somewhat fairly strong acid solution until tomorrow to hopefully get all the crud off.  The HX seem to have cleaned up very well but the boiler still has deposits.  If it doesnt come out ill take some sanding paper to scrape off the inside remains.  I just hope it doesnt have to come to that tomorrow.

                    So as of yet, Im debating what to do with the second machine.  Scrap it and use it for parts, or spend ~$300 to repair it back to operating conditions.  Normally i wouldnt think twice about the 300$ investment but being a college student, I have to weight my options at this point.

                    Back to my actual build.  I got my gaskets in the mail yesterday and it looks good.  The heads are fully refurbished and look very appealing.

                    If anyone has suggestions on what I should do Id be very happy to hear it.

                    My list of things to do to this machine is:

                    Soak the electrical wires in some hot soapy water to clean off coffee stains and let dry after.

                    Clean external panels and polish with rubbing compounds.

                    Clean frame, repair rust damages, and apply one or two coats of fresh paint. Also regarding the paint, I will be painting the frame black but the outer panels I was thinking white with a black la Cimbali logo on it. I hope this doesnt look too.. flashy? Ill be taking suggestions regarding paint schemes :]

                    And assemble late monday afternoon.

                    Till then.


                    • #11
                      Re: New To this site, new to machines

                      The metal tag attached to the boilers should have a manufacturing/inspection date on them which will give you a close approximation of when the machines were made.

                      Java "Gotta love a good project!" phile
                      Toys! I must have new toys!!!


                      • #12
                        Re: New To this site, new to machines

                        Sorry for the late responce, been busy with work but that is no excuse for updating.  I finished cleaning all the parts a couple weeks ago but then was way to busy to finish putting everything back together.  I originally started rebuilding the dosatron version of the m20 hopint to have a volumetric dispense but due to some complications had to stop and redo some work.

                        There were two problems that I would discuss with people who are new to restoration processes like these for commercial machines.  When you are about to purchase one of these guys, please ask to see it run before you.  I made the mistake of buying these blind and not knowing if everything ran before it even started. 

                        The first problem I encountered was leaks everywhere.  10 bar is quite a lot of pressure so you can imagine how badly some leaks would spray out of the machine.  I was even scared of tightening some of the fittings thinking they were going to strip the threads.  But, after going through all the connections, I made sure everything had stopped leaking.

                        The second, the more important problem was the electrical side.  After hooking everything up, I turned the machine on and the heater started, however, the pump refused to start.  Sadly, since these machines are so old, theres very little information online regarding electrical diagrams.  The main problem was that when you press the dose button, the machine would just release a "click" and nothing would happen.  I mean you can imagine the thoughts going through your head when you just hear a click and nothing.  I got lucky because I was browsing for electrical parts and noticed that for the m20, there are two types of relays.  One is triggered by a 24VAC signal, and the other is triggered by a 240VAC trigger.  The smart person that I am, early on in the build, I decided to scavenge the good parts from each machine and put it into a good build.  Well apprently the two machines did indeed come with two separate relays.  The older manual on/off machine used a 240VAC relay trigger that I had put into the 24VAC dosatron relay.  So I realized that that "click" was the relay trying to energize the pump but not having enough power.  After switching the relays there were more promising sounds.  After selecting the dose, there was the very distinct buzz coming from bad electronics.  Turns out the 24VAC relay is bad and needs to be switched.  At that point i decided to redo the machine and reinstall the old electronics with the simple on/off switches.

                        It took one day but everything was rewired and pressure tested to ensure no leaks during operation.  Heres the results.

                        Now that I have working la Cimbali, I can calm down with some good coffee and think about the older one.  I was thinking of rebuilding it to its complete form and putting it on the local craigslist for sale.  It just needs two things, main switch and a new relay.  Everything is cleaned and descaled so I hope there will be somebody local that might be able to pick it up and use it.


                        Short video of the machine in use.  I was using some local coffee beans that were roasted on the 20th and it makes great coffee!  However the steam, I still cannot master.  It is way too much power for me at the moment.  Either I get too much foam, or the milk goes everywhere.  But I will continue experimenting with milk and going through milk by the gallon.

                        Well, I will update later on when I figure out what to do with the other machine. 


                        • #13
                          Re: New To this site, new to machines

                          Nice work!

                          Where does the brew pressure feed to the gauge come from? I have a similar but smaller machine (single group Faema A1) and my gauge is only the boiler pressure. Have thought about swapping the single gauge for a dual like yours.

                          What steam tip does your machine have?



                          • #14
                            Re: New To this site, new to machines

                            Where does the brew pressure feed to the gauge come from?  I have a similar but smaller machine (single group Faema A1) and my gauge is only the boiler pressure.  Have thought about swapping the single gauge for a dual like yours.

                            Theres a very thin tube that goes from the non return valve to the pressure gauge. 

                            Sorry the picture is small, but if you look, there is a pipe (drawn) coming from the pump to the non return valve. From there the line goes toward the group, and one toward the gauge. Im not familiar with your Faema machine but look for the line that goes toward the group and see if there is already a split in there or you can just add a t-fitting to tap into it :]



                            • #15
                              Re: New To this site, new to machines

                              Thanks for the info. Mine is a bit different, the pump goes through the OPV, then the flow meter than to the group. I would have thought the pressure source would be closer to the group.

                              I will have a look inside when I next pull the panels off.