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Thread: Vibiemme domobar super - Pump Noise

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    Vibiemme domobar super - Pump Noise

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    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!

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    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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    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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    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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    Senior Member GregWormald's Avatar
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    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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    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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    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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    Re: Vibiemme domobar super - Pump Noise

    check the pump is in its mounts on both ends

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    Senior Member GregWormald's Avatar
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    Re: Vibiemme domobar super - Pump Noise

    Quote 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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    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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    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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    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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    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?

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    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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    Re: Vibiemme domobar super - Pump Noise

    Quote 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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    Re: Vibiemme domobar super - Pump Noise

    thanks Iaindb - I was aware of Gregs portafilter but it seems its all getting too hard. Ive decided to bite the bullet and get some experts to have a look at it. Im going to take it in today - Ill report back with the fix when I know. Thanks everyone for the replies I really do appreciate it.

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    Re: Vibiemme domobar super - Pump Noise

    Cool, just double check the "experts" are calibrating it to 9 bar with the right flow or whatever you want, as they may not :)

    /endcynicism

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    Re: Vibiemme domobar super - Pump Noise

    My machine (VBM - DS) just came back from a service and is making exactly the noise you are talking about. Frustrating thing is it was not making the noises before it went in for service.

    The pressure stat was corroded out and leaking on the bench (fortunately replaced under warranty) - this is why I sent it in for service.

    Its very loud and im concerned about doing damage to the machine so are not using it.

    Im taking back to the service agent Friday to get it checked out.


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    Re: Vibiemme domobar super - Pump Noise

    Apparently my over pressure valve was set incorrectly not allowing enough water to return to the water tank. I didnt have a brew pressure gauge on my machine so thought it was best to get it done by the professionals and get an all round service whilst there. If its just that pump noise it should be a fairly quick fix Id imagine ( if it is indeed the OPV that is the problem). There is a users manual put out by 1st line in the US that has good instructions on how to do this if you like to tinker and have the ability. I dont have the link on me but it wasnt too hard to find on google.

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    Re: Vibiemme domobar super - Pump Noise

    The pressurestat shouldnt have anything to do with the pump, so unless they touched something else, perhpas the noise is coming from elsewhere?

    It could also just be filling, if they emptied the boiler - my HX is noisier when filling from empty than with water already in the boiler.

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    Re: Vibiemme domobar super - Pump Noise

    Pump noise is unlikely.

    Its much more likely to be vibration caused by contact of one of the copper pipes making contact with either boiler or tank cradle- most likely as a result of bumps in transit. The fix is to provide clearance.

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    Re: Vibiemme domobar super - Pump Noise

    Ill open the case up tonight and take a look. It does sound like its vibration contact on internal components.

    Whats interesting about it is that the noise goes away when the brew pressure is built up pulling the shot. As soon as the pressure drops the noise comes back.

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    Re: Vibiemme domobar super - Pump Noise

    As far as I understand, when the pump goes under pressure, the shuttle or valve that pushes the water out the end doesnt move as far, since its not physically connected to anything, just moved by an electrical current around the outside. This meas that as the pressure rises, the total movement is less, which means it would be vibrating slightly less.

    I assume this is why they are quieter when under a bit of pressure than when pumping air, for example. It also means that if its knocking on anything, that will decrease slightly under some pressure, which is what you notice.

    I think ;)

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    Re: Vibiemme domobar super - Pump Noise

    thanks iaindb appreciate the response

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    Re: Vibiemme domobar super - Pump Noise

    So I took the cover off the case and noticed almost immediately a couple of the hoses were touching the base of the machine. One of them is an insulated hose which has the metal ends on it. It was these making the noise.

    Adjusted slightly by bending up off the base of the machine and it went quiet straight away.

    Thanks for your input.

    A



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