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Rebirthing a Bezzera BZ40

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  • Rebirthing a Bezzera BZ40

    Hi there, I was visiting a friend the other day and I mentioned I was having trouble with an ebay coffee machine purchase and he said...I have a machine down in the garage, been there years. Well my ears picked up and we went and dug it out and it was like American pickers..."it's in here somewhere". Finally spotted it, and sure enough it was covered in dust and spiders webs. I got it home and did some research and it seems to be an early Bezzera BZ40.
    I got it stripped down and clean it out, hooked it all up and was not a good start...it kept tripping my safety cutout. So after much checking here and there I got it running this morning. The heater working, pump working, water from the tap, steam from the arm....but no water from the head. The pressure went up to 1 bar, then it started cutting out again...the relay trips.
    Just looking for any pointers, I'm fairly sparky minded as I build valve amps.

    Cheers

    Don
    Last edited by gingercat777; 12 March 2013, 10:21 AM.

  • #2
    Update, It was cutting out after 2 secs of turning on, have changed the mains lead, disconnected the heater again, still does it.

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    • #3
      I recently had an identical problem with my Rancilio S24, you possibly have no water in the boiler and the element is firing up without any water causing it to open circuit and trip the switch. Also in regards to no water coming out from the group head. I had the same issue and because my machine was stored for quite a few months the jet in the 3 way valve was blocked and not letting water through to the group head.

      Have a quick look at my thread here http://coffeesnobs.com.au/brewing-eq...ey-switch.html

      Hope this helps. I previously rebuilt a BZ35 which is an almost identical machine. Only differences I beleive is your machine has 2 heating elements and it also has gauges where mine didn't.

      -Brendon

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      • #4
        Thanks for that, there was def water in the boiler, but obviously nothing pumping through. I'll have a looky at that side of things and just check bits step by step.

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        • #5
          Yeah well that's what I'd personally suggest you do. Just follow the line back from the group head.

          Go download the schematic diagrams from here http://bezzeracoffeemachine.com.au/i...load&view=item

          Those were my best and closest friend when I rebuilt my machine. Head over to page 23 Tav. 07 that is basically the group head path. If you have a blockage in any part's it will be one of the ones on that page. Or page 27 Tav. 08 which is the 3 way valve assembly which had the blockage on my Rancilio.

          Hope this helps.

          If you want to email or PM feel free

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          • #6
            Cool, I hunted high and low for a parts diagram, mine is prob the most basic model way before that one.

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            • #7
              Yipppeee, I got a coffee out of it finally. Well it's not perfect yet and I did nothing dramatic to fix it, it sure is a temperamental machine. All I did was check the heater, flushed/filled the tank...this could be what clinched it? Checked the relay, 8ohms across the winding terminals...that seemed within spec. Put it back in and I thought why not leave of the pressurestat terminals (these were initially overheating and carrying on at the very beginning when I first turned on the machine) to see if the pump will run.....it did. Also water came out of the head....finally!! So kept checking and letting it run for longer periods....I plugged in the other terminals at the relay and was expecting the ol cut out....nope stayed on...and the heater was up and away. Let it get to 1bar....1.2...1.3.....1.5bar...click turned off, pressurestat works. Ran the pump and the only niggly prob is water is constantly flowing from out of the top of the 3-way valve into the tray. So tomorrow I'll check that, hope it's not the solenoid.
              Anyway I managed to squeeze a couple of cups before dark....I'm doing this outside. Oh yeah, the steam wand is terrible, it's a little tiny thing....plenty of pressure....just not doing the stretch and roll very nicely. Oh well, I can worry about that later.

              Thanks for the helps

              Don
              Last edited by gingercat777; 12 March 2013, 08:29 PM.

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              • #8
                Ginger can you tellme what kind of pump it have! I am rebilding bz40 too. But but iam not sure about the pump that i have!

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                • #9
                  Originally posted by brendogs View Post
                  I recently had an identical problem with my Rancilio S24, you possibly have no water in the boiler and the element is firing up without any water causing it to open circuit and trip the switch. ...

                  -Brendon
                  That is very interesting. How does the absence of water open circuit ? And trip the switch?

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                  • #10
                    Originally posted by Evascroll View Post
                    Ginger can you tellme what kind of pump it have! I am rebilding bz40 too. But but iam not sure about the pump that i have!
                    if the pump is small and noisy it is a vibe pump,the most common, a rotary pump is about the size of a car alternator and is much quieter if that helps any.

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                    • #11
                      Originally posted by C-man View Post
                      if the pump is small and noisy it is a vibe pump,the most common, a rotary pump is about the size of a car alternator and is much quieter if that helps any.
                      Thanks C! The one that i have it is a rotary pump! Mine is a procon model! By the way how do you adjust the brew pressure on this machine!

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                      • #12
                        Originally posted by gingercat777 View Post
                        Update, It was cutting out after 2 secs of turning on, have changed the mains lead, disconnected the heater again, still does it.
                        Ginger about this problem i find out that if the pole form the heaten element are oxidated and dont make god contac i will turn off! (happen to me) just clean the contact using sand paper waalaa!

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                        • #13
                          Thanks for that, after a few days of use the machine is settling down. The steam arm on this machine is awful, must be for the days of the shaving foam.

                          Evascroll, here are pics of my machine...not sure about the high pressure on your machine, my gauge goes to 2.5bar


                          Bezzera BZ40 Photos by telenut62 | Photobucket

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                          • #14
                            I'm interested in hearing how you both (Evascroll & gingercat777) get on with your projects.

                            I've just acquired a machine that looks almost identical to the one in gingercat777's photobucket, except mine has a rotary pump. Based on the serial I think it is a 1991 build. Currently the lights come on using the power switch and the pump activates (and relay clicks) when the espresso switch is pressed. I've only tried both of these for a few seconds as with everything else disconnected the pump won't pull any water from a container.
                            Click image for larger version

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                            I've removed the spring and ball bearing from the pump and it had a reasonable amount of corrosion on it and I've given it a soak in cirtic acid but I think the pump still needs a little more TLC.
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                            Following from here it seems the next component down the line (OPV?) has also blocked up
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                            I at this stage I haven't yet made it into the boiler to inspect its condition, I'm having some trouble removing the copper pipe from the HX to the Head. The lock nut is completely undone but no amount of gentle encouragement will separate the pipe from the HX. Any suggestions?

                            This is my first project on a machine of this style (I've worked on EM6910's and the like replacing switches/seals, etc). I would appreciate any advise.

                            I suspect a good start would be sourcing replacements for the rubber components in my above photo, does anyone have any recommendations on where I might source these?

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