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  • Oscar II - water flow stops while flushing

    I have the EXACT same issue like he has here (except I don't have any mods yet):
    https://coffeesnobs.com.au/forum/equ...-during-a-shot
    https://www.youtube.com/watch?v=FziX-gVZEjk


    Thing is I have replaced the pump - and the problem stays!
    I also disassembled the 0.7 orifice and 3 way solenoid... cleaned the best I could.

    Any suggestions?
    What is the "pump non return valve" - is it the Neplax viton - part 98120001?

  • #2
    Anybody?
    Where is the no-return valve in Oscar 2? I haven't found it.

    Comment


    • #3
      The pump non return valve is in the output side of the pump. It's just a ball with a spring behind it.
      you need to flow test your pump,(300ml in 30sec) at the pump output.
      maybe your pump wasn't so new.. or you have dirt it your water tank.

      ​​​​

      Comment


      • #4
        I have a Musica. There is another non return valve in it. I think it is just prior to the hx circuit. So the pump cycles to prepresurise the hx (through that noreturn valve with 3way closed), then cycles again for preinfusion (3way open to pf), then it starts the brew.

        Not the neplax. It's the expansion valve

        Comment


        • #5
          Click image for larger version

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          Item 2 it called a calibrated orifice. I'd look in there for a blockage too. This is the item I said is a non return valve...

          Comment


          • #6
            You want more?....
            Click image for larger version

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            It's this bit that I arrowed for you. Hope that solves it..

            After that, check the gicleurs in the back of group head. Inside where the pipes connect on the back.

            But a pump flow test will show you where to look

            Comment


            • TheTool
              TheTool commented
              Editing a comment
              I have disassembled the one-way valve you marked and also the group head, and inspected the gicleurs...
              there was some scale and rust but nothing too dramatic so I don't think that's the problem
              anything else to check?

          • #7
            Thanks for the replies!
            Is the green plastic check valve located where I circled?

            For sure the pump gives 300ml in 30secs, when the boiler gets to pressure the water quickly gushes ous 300ml even in less then 30secs but then the flow slows down and stops for about 10 secs...

            Its a brand new pump and I tried to clean the orifice, but I already ordered a new 0.7 orifice with the OPV...
            Attached Files

            Comment


            • #8
              Here is a video that shows the issue clearly, with the shower screen removed.
              There are micro stops in the flow until it stops for a few seconds. The cup capacity is 350ml
              Last edited by TheTool; 1 August 2020, 09:58 AM.

              Comment


              • #9
                Originally posted by Jackster View Post
                You want more?....
                Click image for larger version

Name:	Screenshot_20200730-072101__01.jpg
Views:	140
Size:	175.4 KB
ID:	836464
                It's this bit that I arrowed for you. Hope that solves it..

                After that, check the gicleurs in the back of group head. Inside where the pipes connect on the back.

                But a pump flow test will show you where to look

                I have disassembled the one-way valve you marked and also the group head, and inspected the gicleurs...
                there was some scale and rust but nothing too dramatic so I don't think that's the problem
                anything else to check?

                Comment


                • #10
                  What happens if you test pump flow directly out of the pump? Say at the pipe on bottom of that valve.

                  It kinda looks like you are trying to pump air. My machine needs around 1/4 tank minimum or it seems to suck air.

                  ​​​

                  Comment


                  • #11
                    Originally posted by Jackster View Post
                    What happens if you test pump flow directly out of the pump? Say at the pipe on bottom of that valve.

                    It kinda looks like you are trying to pump air. My machine needs around 1/4 tank minimum or it seems to suck air.

                    ​​​
                    Tank was more than half full, tested pump rate after 0.7 gigler:
                    About 300ml in 45 secs. it took 55 seconds to fill the 350ml cup.
                    https://www.youtube.com/watch?v=UVv3TIRk580

                    good thing I ordered a new gigler...

                    Comment


                    • #12
                      I see your video. Not sure where your test point is.
                      i see it's a plastic pipe, so can assume you are either before or after the valve I indicated previously.
                      you need to keep testing back closer to the pump. This will show you where the restriction is, or if the pump is bad.

                      I see no part on the diagram listed as a gicleur. So I don't know what you have ordered or where it goes. Traditionally (and in the case of the 2 gicleurs I bought) they fit into the hx pipes that feed the grouphead.
                      Though, I am not familiar with the calibrated orifice at item2. Is this the thing you are calling a gicleur?

                      Comment


                      • #13
                        Originally posted by Jackster View Post
                        Though, I am not familiar with the calibrated orifice at item2. Is this the thing you are calling a gicleur?
                        Exactly, orifice=0.7 gicleur... The test point is after the orifice only.

                        Comment


                        • #14
                          Maybe, your pump is fine, and the restrictor is doing it's thing, and your flow numbers are correct at your test point.

                          ​​​

                          Comment


                          • #15
                            Originally posted by Jackster View Post
                            Maybe, your pump is fine, and the restrictor is doing it's thing, and your flow numbers are correct at your test point.

                            ​​​
                            Thats weird because I asked a friend - oscar II owner and with his machine the water flow never stops, he even sent me a video showing that.
                            On my machine if I do a long flush, afterwards there isn't enough pressure in the system and sometimes it can take 5-10 seconds till it starts flowing again.

                            Comment


                            • level3ninja
                              level3ninja commented
                              Editing a comment
                              Jackster is saying that you aren't testing at the right place, not that you don't have a problem
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