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  • M27 water fill wont shut off.......

    Hi everyone,

    well I finally got the old girl back together after a full descale and new seals & gaskets.

    Fired her up, heard a clunk and then I could hear the boiler filling with water.   Problem is, it just continues to fill and never stops.

    Ive pulled out the level probe and its as clean as a whistle.  

    Next I thought if the the solenoid works ok to start the fill then its not the problem either(?)   Maybe I should swap it with one of the other solenoids to see if it makes any difference.

    Ive also pulled apart the boiler supply solenoid valve and it looks pretty good.   (see pics below).    





    Not sure how to tell if the valve is working ok or not.  With the shaft removed, if I gently blow into it, it blows freely back away from the boiler, but has pressure when blowing in toward the boiler.

    Any ideas?

    thanks.

  • #2
    Re: M27 water fill wont shut off.......

    I trust your not using straight RO water...

    If it is too clean the probe will dot detect the water as there is no conductivity.. Just a thought..

    AM

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    • #3
      Re: M27 water fill wont shut off.......

      Its just regular mains pressure water through a bombora water filter, a Cimbali pressure reducer (inside the machine), then straight into the solenoid valve.

      What should I be seeing if I check resistance on the level probe?

      Comment


      • #4
        Re: M27 water fill wont shut off.......

        Hi Borat could be a circuit problem- I had to replace an auto fill card on a Boema.
        Just for my own info, do you put the water filter before the pressure reducer? Ive got the reverse and my Faema seems to struggle with filling
        Brett

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        • #5
          Re: M27 water fill wont shut off.......

          Yes, Ive got the water filter before the pressure reducer. The reducer is part of, and sits inside the machine.

          Comment


          • #6
            Re: M27 water fill wont shut off.......

            Been thinking about the problem.....

            1.   With mains water connected but the machine powered off, no water flowed into the boiler.

            2. Power on, the solenoid clicks, the valve opens and the boiler fills.

            3.  Therefore, both the solenoid and the valve must be working ok (?)

            Maybe a fault with the probe (but it looks ok too)

            So, I took out the board and had a look.  Heres some pics.    Anyone know how to test the function of the board?  

            I cant see anything obviously burnt out, or dry joints.  Although it looks like some repairs or resoldering has been done in the past.








            And heres schematics of the electrics, the last one shown on the outside of the casing that the board came from.    Looking at these can anyone see which component relating to the autofill might need replacing?

            thanks.

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            • #7
              Re: M27 water fill wont shut off.......

              Hhhmmm.....does the M27 have a probe or a float for the water level detection?

              If its a float you may need to adjust the gap on the magnetic reed.

              If your machine has the part circled in yellow push it in towards the boiler and see if it stops filling. If so adjust the screws until it fills to the proper level.


              Java "Knowing when to stop is a good thing!" phile

              Toys! I must have new toys!!!

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              • #8
                Re: M27 water fill wont shut off.......

                Hi Borat
                my board had been resoldered- in that case it was a transformer. With mine it was a safety function which kept turning the machine off- telling it there was no water.
                The boards are usually replaced as a whole. It may be worth biting the bullet and getting a tech to look at it as you wouldnt want to spend on the wrong part (autofill box from coffeeparts.com is $239)
                Brett

                Comment


                • #9
                  Re: M27 water fill wont shut off.......

                  Hi guys,

                  thanks for the replies. The boiler has a probe, rather than a float. I took the probe out of the boiler; the teflon bit looks intact, and the bit that was inside the boiler was spotless without any scale at all.

                  Im tending to think its a fault with the board. I read somewhere about removing the wire to the probe and grounding it during the autofill. If the solenoid doesnt clunk and the fill stop, then its likely the board is the problem. Found this on: http://www.home-barista.com/espresso...lem-t7147.html

                  Anyone know someone who can diagnose and repair the board? I really dont want to have to spend another $200 for a new one.....

                  From what Ive read so far, the components on it are pretty cheap. I can solder ok, but absolutely no idea on how to work out which bits need replacing. Maybe Ill just replace the relay for a start and see if that helps.

                  Comment


                  • #10
                    Re: M27 water fill wont shut off.......

                    Originally posted by 636E736075303332010 link=1247055437/8#8 date=1247137168
                    Hi guys,

                    thanks for the replies.    The boiler has a probe, rather than a float.  I took the probe out of the boiler; the teflon bit looks intact, and the bit that was inside the boiler was spotless without any scale at all.

                    Im tending to think its a fault with the board.  I read somewhere about removing the wire to the probe and grounding it during the autofill.  If the solenoid doesnt clunk and the fill stop, then its likely the board is the problem.   Found this on:  http://www.home-barista.com/espresso...lem-t7147.html

                    Anyone know someone who can diagnose and repair the board?   I really dont want to have to spend another $200 for a new one.....

                    From what Ive read so far, the components on it are pretty cheap.  I can solder ok, but absolutely no idea on how to work out which bits need replacing. Maybe Ill just replace the relay for a start and see if that helps.
                    My guess in the first instance is teh black box...  It appears to be the one that has been replaced previously.. A bit hard to see when looking at the bottom of the board and trying to flip in teh mind as to the placement of components..

                    Now if you were in Brisbane I could have it solved in a flash :-)

                    I will see if a mate ... A top Fishing mate and one of the best Electronic minds I have ever met / dealt with...  But he hates the WEB and Forums...   PM me your e-mail addy and I will reply to you and him with a copy of your post...

                    Part of teh problem is that troubleshooting this stuff really requires hands on... So many things can mean so much and hands on and a meter is like a picture.  It tells a thousand words..

                    Comment


                    • #11
                      Re: M27 water fill wont shut off.......

                      hey Borat
                      i know this sounds to simple but you have plugged the board in the right way round right........
                      and any of the wires to sensors / solenoids etc
                      not swaped them over or something???

                      only cause i plugged in a wire back to front on my "project carmila" and it did not like it. that mistake was even after i marked the wires and took pics........ took me a while but then i picked up on it

                      go back over the wires and check again, hope its a simple fix for you

                      Maheel

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                      • #12
                        Re: M27 water fill wont shut off.......

                        Thanks Angermanagement - PM sent.

                        Hi Maheel, yes I purposely left the wires on the solenoids when I took them off the valves- so they should all still be in on the right terminals.

                        The autofill board only came out after the machine was fully reassembled, so all those wires were also still in their original positions.

                        Good point though, it was worth checking.

                        Comment


                        • #13
                          Re: M27 water fill wont shut off.......

                          Originally posted by 4D405D4E5B1E1D1C2F0 link=1247055437/11#11 date=1247142934
                          Thanks Angermanagement - PM sent.

                          Hi Maheel,  yes I purposely left the wires on the solenoids when I took them off the valves- so they should all still be in on the right terminals.  

                          The autofill board only came out after the machine was fully reassembled, so all those wires were also still in their original positions.

                          Good point though, it was worth checking.
                          Mate said what I was thinking... Those little marks on the transistors... They marks for chips / burn marks ??


                          The two together ate a wired as a Darlington pair driving the relay and teh other is amplifying the signal from your sensor probe..

                          The diode across teh relay is to manage teh back EMF of teh coil and if it has blown... or any of teh three transistors then the board = STUFFED.

                          His comment was... Have all teh components sitting in his junk draw... ;D

                          Problem... Without the unit in his hand or Mine... We can do nothing more... :-[

                          Comment


                          • #14
                            Re: M27 water fill wont shut off.......

                            Originally posted by 424F524154111213200 link=1247055437/11#11 date=1247142934
                            hanks Angermanagement - PM sent.
                            Bugger me .... NOT


                            Well all 3 BC547 have popped :P

                            Now, I would usualy head off to my mates and rebuild ASAP from his supply of parts...

                            However as you may be aware... She in control of $$$ and the quality of my time here on earth.. Is arriving back from Italy TONIGHT 8-) : :-*

                            So if I play my cards right :-? :-*

                            That means your job will have to take second priority

                            Will keep ya informed... Would like to think back in the bag to you by Friday..

                            Oh... Thanks for including teh return bag... Nice thought.

                            Comment


                            • #15
                              Re: M27 water fill wont shut off.......

                              No problem at all

                              Heres the diagram & pics I tried to send via PM......





                              cheers.

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