JahLaza shot up to above 15 bar at about 6 seconds and then settled back down around 8 bar after about 12 seconds or something. The shot them took about 50 seconds to finish. I turned the machine off both times and made a couple

Could be it’s ground to fine and Cruzet many years ago made a change to the drive unit (Cruzet a french company make the mag drive impule unit, FOT Italy make the rest). The drive unit requires less impulses for a given speed. My pump acceleration figures are for the very old drive unit. Use much lower values and it should be better. your acc is probably so fast the PID can’t react in time to prevent the overpressure.

Why don’t you put your pump PID settings and Pump Acc numbers up here, then you can be helped better.

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      DavecUK pump kp 10.0. Ki 0.24. KD 90. Pump acc 410. Everything else as per factory settings. I did change bean yesterday - on to a blend of Ethiopian/Sumatra with a wide range of bean size within actually. Maybe it’s this bean blend/grind as you point towards. I’ve been through a lot of different beans with the Vesuvius and never experienced this. So maybe I should reduce pump acc speed?

        From another forum where Dave C used to be said (dated 2-16-2021) “If its a V sold in the last year or 2, then the Cruzet, who make the induction part of the pump for Fluid-o-tech changed the impulses per second parameters. This means the pump acceleration numbers may have to be far lower than the ones in my documentation… giving a smoother transition from one pressure stage, to another”.

        I remember what I read in another forum Paolo from ACS recommended to lower the pump acceleration below 150 for those who have the Cruzet induction part if your pressure overshoots.

          Kape17 thanks but I’m not sure this would explain what’s happening. Why would it jump to 15+ bar in the middle of a 2 bar step? Higher pump speeds attempt to achieve pressure changes faster. Why would it happen 50% of the time, and again half way through a 2 bar step that lasts 8 seconds

          Edit: The settings I have listed above have worked using various profiles including the current one over the past months with no issue

            I reduced pump acc to 330 this morning and shot pulled fine. Still don’t understand why it would suddenly start to jump in middle of a step rather than when transitioning from one pressure to the next.

              JahLaza If for any reason it sensed a momentary reduction on pressure….bam away goes the pump. With high acc, it can peak super fast against a resistant puck.

              A few pressure profiling machines which will remain nameless actually told you the pressure they were trying to make and not actually the pressure they were making. The Vesuvius tells you immediately and accurately what the momentary pressure is.

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                  DavecUK thanks Dave. I get that logic, but strange that’s only happening now. The above settings had been in place for months now. I’ve used many types of profiles and lots of different bean types, the only time I observed funny operation was when it would either over shoot (not by much more than a bar or so) or not reach target pressure in a step. That would be rectified by changing the speed or kp value, but as I say the above settings had been in place with no issue for a good while, but shooting up above 15 bar half way through a 2 bar step just seems odd! Everything seems fine now anyway, thanks for you and other’s input (It’s a great machine😊!)

                    As previously said this happened on my machine as well twice or three times . Same as yours around year old.

                    Very odd and doesn’t seem right at all. The group pressure gauge didn’t register any increase in pressure and was showing 0 yet the pump was going at 15 bar .

                    I’m glad it didn’t happen for a while now.

                    mailto:kafar@btinternet.com

                    In the recent weeks I noticed the pressure on the group gauge running around 1 bar higher than shown on display. I would normally ignore it but they were always showing perfectly same pressure since day one and remember reading @DavecUK post about this.

                    What could be the issue ?

                    Video a bit short as first shot of new beans so need to grind tad finer but basically when the display shows 8 bar the group is 9 as it falls to 7 the group will show 8 etc.

                    mailto:kafar@btinternet.com

                      prezes As the pressure is equal in all parts of a system that is sealed, which the brew circuit is at the inlet end….the pressure differences can only be due to either the:

                      • Software PID fluctuations that the system reads but the gauge doesn’t react to
                      • Software PID fluctuations that the system doesn’t respond to, but the gauge does read
                      • gauge reading incorrectly
                      • pressure transducer reading incorrectly

                      As the gauge is a mechanical device, using a coiled bourdon tube, it’s never likely to be that accurate, or consistent across the range of readings e.g. it might be accurate at 5 bar, over/under read at 2 bar and 10 bar? They can also become less accurate over time.

                      What happens if you try it on a blind filter with the machine set to a constant 9 bar…

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                          DavecUK thanks @DavecUK as said only picked up on it as it always read perfectly same so noticed the difference. Don’t want to be overly worried without reason but rather nip issues in early stages.

                          mailto:kafar@btinternet.com

                              prezes I don’t think there’s anything to be worried about, the gauge perhaps overreading by 0.3 or 0.4 bar.

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                                  prezes Since I have bought my V (three years ago) there has always been a difference between 0.5-07 bar but as @“DavecUK” mentioned we have two different systems of detecting the pressure so I decided this should not be out of the norm. The most important thing is, is your coffee what you expect/like it to be? 😀

                                  Current setup: ACS Vesuvius, Nuova Simonelli Mythos One. Past experience, Nuova Simonelli Apia 1 gr., San Remo Capri 1 gr., Bezzera BZ 35e, Fracino Heavenly. Anfim Super Lusso.

                                  Contact me at: john_yossarian11@yahoo.com

                                      prezes I would swap out the gauge on the group or get it re calibrated if I was worried or curious..?

                                        6 days later

                                        I think I got to the bottom of this. This morning noticed the group gauge is sitting at around 0.5 bar when not brewing. I was sure I had a photo from last year to check if it was always like this and it wasn’t so definitely issue with gauge. Anything I can do about it or is it replacement only ?


                                        mailto:kafar@btinternet.com

                                          prezes As I thought it’s the gauge..you can “try” twisting the outer shell a tad, but I think it’s keyed with a square piece, so it won’t adjust it….replacement is the only option I am afraid.

                                          Note to self: “the OCD is strong in this one” 😁

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                                              Do you need that gauge there?

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