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Vibiemme domobar super - Pump Noise

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  • Vibiemme domobar super - Pump Noise

    I just have a question for those that know more about the normal noises a Vibiemme Pump (Ulka E type EX5 230V 50Hz) makes when its under pressure.

    For the most part it behaves normally and is fairly quiet, but when I try and pull a shot that is a little tight or try and back flush the pump pulsates making a stuttering noise and the return line back into the water tank shakes. Is this normal? Is there and adjustment that can be made to something to tame it? I dont recall it making it in the beginning when I first started using it - it seems to have just developed since returning it to service.

    Any replies greatly appreciated!

  • #2
    Re: Vibiemme domobar super - Pump Noise

    My first thought would be that the pressure relief valve needs a clean and lube and a readjustment, and possibly a replacement spring. Depending on the service it received, maybe a pump mount was left loose. Does the brew pressure gauge reflect the noise (wider needle swing than normal) and is the pressure in the range you would expect when backflushing?

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    • #3
      Re: Vibiemme domobar super - Pump Noise

      As far as I know it hasnt received a service yet in its 6 years! This model is the older model and it doesnt have the brew pressure guage only the boiler pressure gauge. Ill try adjusting the pressure relief valve. Might seem like a stupid question but would I adjust it up or down? The pours on the last one seemed about the right speed but the pucks in general have been soggy (this also could be my dose and grind which Im still working on).

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      • #4
        Re: Vibiemme domobar super - Pump Noise

        Ok - I tried adjusting the pressure relief valve both up and down about half to three quater turn in either direction while the pump was running and it didnt seem to change in tone and the pulsating continued unaffected. I reset the valve screw to approximately where it was originally. The pump mounts seem to be in good condition and order from what I can tell. Any more suggestions?

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        • #5
          Re: Vibiemme domobar super - Pump Noise

          The pulsing sounds like lots of water going out the return to the tank. This happens because the pump delivers about 15 bar and the valve that reduces that to 9 bar shunts the excess back to the water tank.

          When the pull is really slow, more water gets pushed that way.

          Greg
          Not an expert opinion, just from watching/listening to my VBM.

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          • #6
            Re: Vibiemme domobar super - Pump Noise

            Thanks Greg,

            Should it be doing it every time the pump is under some load? Does yours do it everytime you backflush? I dont seem to recall it do it initally even when I backflushed.

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            • #7
              Re: Vibiemme domobar super - Pump Noise

              I have attached a youtube link showing the pump pulsating. The high pitched chinging is the glass on top of the cup warmer not the pump. Sorry about the poor audio quality - just turn your volume up

              http://www.youtube.com/watch?v=DxgoYiPLN2g

              Thanks Pretzal

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              • #8
                Re: Vibiemme domobar super - Pump Noise

                check the pump is in its mounts on both ends

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                • #9
                  Re: Vibiemme domobar super - Pump Noise

                  Originally posted by 3210071618030E620 link=1323091059/5#5 date=1323130398
                  Thanks Greg,

                  Should it be doing it every time the pump is under some load? Does yours do it everytime you backflush? I dont seem to recall it do it initally even when I backflushed.
                  Sorry mate, I cant answer either of those questions--the VBM is gone, and my current machine doesnt have a pump!

                  Greg

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                  • #10
                    Re: Vibiemme domobar super - Pump Noise

                    Thanks Mischa,

                    The pump mounts on both ends look good. I tinkered a little more with the pressure reflief valve tonight and when I screwed it one whole turn the pulsating stopped. So did the water returning to the tank. Naturally I backed it off again as water not returning is very undesirable for pump life. I then decided to take the pressure relief valve off and soak the whole thing in caffeto restore descaler as I thought it might have a bit of scale in it that is somehow inhibiting its smooth return to the tank. This was RandyGs suggestion which I was hoping to avoid, but having tried other ideas this one seemed like the next step. Its soaking now so hopefully that will do the trick...

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                    • #11
                      Re: Vibiemme domobar super - Pump Noise

                      Ok so I soaked the bypass valve for about an hour and put it back together - no joy the machine still pulsates. Is it even worth replacing all the o rings, gaskets and spring inside the bypass valve?

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                      • #12
                        Re: Vibiemme domobar super - Pump Noise

                        A few years ago when a shipment of VBM DSs arrived in the states had incorrectly specd pressure relief valve springs. It caused unpredictable pressures. When the updated spring was installed the adjustment became very linear and easily adjustable.

                        The O-rings just keep water from getting past the adjustment screw.

                        Since you were able to get the pump to operate normally with the pressure all the way up (no return through the relief valve when tightened all the way), the safe assumption is that the problem is in the relief valve and not the pump. That could be a worn pressure relief valve bore or worn piston.

                        Cheap possible fix: New spring and piston. Use a bit of silicone lube on the O-rings and piston bore

                        Not so cheap: Replacement relief valve.

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                        • #13
                          Re: Vibiemme domobar super - Pump Noise

                          Ok so assuming I can get hold of the parts for the cheap fix - Im still going to need a portafilter with a pressure gauge to be able to correctly set the brew pressure right (as my model doesnt have the gauge). Otherwise it would be pretty hit and miss wouldnt it?

                          Comment


                          • #14
                            Re: Vibiemme domobar super - Pump Noise

                            I wasnt aware that you had no brew pressure gauge. You can attach a gauge to the threads on the bottom of a standard portafilter after removing the spouts. Carry it to the local hardware store and find a brass fitting. Remove the basket and examine the top edge of the portafilter. It must have a continuous "edge" with no breaks. Then check to see if it will lock without a basket. if so it will work fine. Otherwise it gets more complicated. You will also need an oil filled gauge as the standard gauges will bounce the needle all over making them very inaccurate.

                            Also, before going any further, verify that the bypass hose which leads back to the reservoir has no kinks and is not pinched. That has a slim potential to give the symptoms you describe (although highly unlikely).

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                            • #15
                              Re: Vibiemme domobar super - Pump Noise

                              Originally posted by 604255444A515C300 link=1323091059/12#12 date=1323209598
                              a portafilter with a pressure gauge
                              Greg Pullman to the rescue! Unless you want to buy your own, check out this thread

                              which is what many of us have used for this purpose.

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