Re: noise when pumping without coffee. normal?
Hi, thanks for the quick response! It would be great if htis was a normal noise - I dont think I have it in me to pull it apart again!!!
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Re: noise when pumping without coffee. normal?
Damian,
I think your reasoning is spot on.
On my La Cimbali there are two flow restrictors (one for each group). These provide a slow ramp up of pressure to provide pre-infusion. With a puck or blind filter you hear the water rushing through the 0.8mm hole for maybe a second - until the pressure in the PF starts to build.....
But if the group is left open.... then the "venturi" noise continues as the water pressure drops from 9 bar to zero across this 0.8mm hole......
Not familiar with the Rancilio...... but wouldnt surprise me if it does something simlar.
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noise when pumping without coffee. normal?
Hi,
I have been restoring a Rancilio 2 group S20 midi DE. All is going well - completely stripped it, cleaned and descaled, replaced all the seals and gaskets, and put it back together. Just made my best coffee in years (actually, ever!) on it, so it was worth the effort! I had been doing the same roast for a good year or so, so I was very surprised to see how different it tasted on another machine.
I only have one noise I am not sure should be there. I think it is coming from the gicar flowmeters (yes, a separate noise from each group when that group is activated). I get the noise only when I pump without coffee in the filter. when coffee in in there I dont get the noise. when I put in a blind filter, I hear it for about .5 seconds, then it stops. Im pretty sure there are no leaks, and dont think it is an ovp. it still makes then noise when I run the machine cold. The noise is hard to describe, the best I could do is say it sounds like pressurised water being squirted (pressure set to 9.5 bar).
I noticed when I had the flowmeters out for cleaning that there is a very small entry hole into the meter. My theory is that this is the point of most resistance in the hx/thermosyphen/group line from the pump, and this results in the pressurised water making a bit of noise through this point when there is no coffee. Does that sound possible or am I looking at another problem?
Any help would be great.
Thanks, Damian.

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