Paolo_Cortese the only thing is that the problem faced have nothing to do with temperature but with profiling in some conditions

I do not want to take this further and won’t post anything else but just to be sure, what do you mean with “profiling in some conditions”? My Vesuvius performance was spotless in any condition. I use to have two profiles “to go” and have experimented a lot with others: shorter, longer, lever like and so on. In every case the machine performs well. With this very same profiles, with the very same pid settings, the very same coffee, filters, puck prep, etc, because I’m who makes espresso at home, with all this unchanged BUT with the steam boiler hot, the machine fails. No matter if it’s the first espresso of the day, the second or the last one. Believe me, I have tried everything and the only fact that remains the same is the different behaviour depending on service boiler temperature.

      tocateclas BUT with the steam boiler hot, the machine fails. No matter if it’s the first espresso of the day, the second or the last one. Believe me, I have tried everything and the only fact that remains the same is the different behaviour depending on service boiler temperature.

      Is the brew water preheat system on when this happens (HX on setting). As this could be the only possibility, not certainty that back pressure from the HX tube may make the PID behave oddly with respect to pressure. Although even at 130C only around 1.7 bar is the push force required to overcome it (possibly more if the expansion of that very small amount of cold water in the HX tube causes a higher pressure momentarily). The pump would then move to a high pressure briefly to overcome it.

      HX on is a setting for cafes, not home use, so it should never be used otherwise.. With HX on, the way to the group closes after the shot, and the systyem is sealed again.

      HX off closes the route via the HX tube and water routes around the service boiler to the group. The only way I can think that a similar issue “might” happen as with HX on is if the solenoid that prevents water entering the HX tube is leaking back slightly and raising the pressure in the other side of the system… in between any 1 way valve and the solenoid leading to the brew boiler.

      The lower temp of 120C, may be insufficient to raise the pressure enough to cause the issue?

      All guesswork?

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        Thank you @DavecUK .

        No, HX is been always off. I tried with hx on just to check if there was any variance but there was no difference being on or off.

        As you told me a couple of years ago (if I remember well) HX could be a cause, I replaced this solenoid just to be safe (beside right panel, next to the steam boiler). Apart from this solenoid I replaced the water distributor and auto fill solenoid, everything on this piece but the pressure sensor.

          DavecUK Not a pressure sensor problem, I’m sure it’s not.

          Regarding your concern about the HX and despite knowing it’s properly closed by the solenoid: could it by bypassed or cut? I mean if there is any chance to block this hx circuit and let the brew circuit shorter and free from its possible incidence. Sorry it this is a nonsense, I’m not a technician!

              tocateclas Regarding your concern about the HX and despite knowing it’s properly closed by the solenoid: could it by bypassed or cut? I mean if there is any chance to block this hx circuit and let the brew circuit shorter and free from its possible incidence. Sorry it this is a nonsense, I’m not a technician!

              Yes this could be done.

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                  DavecUK Thank you again. If it’s not too complicated it would be nice to try. I don’t know if this makes any sense but there are not many things to try.

                      tocateclas Thank you again. If it’s not too complicated it would be nice to try. I don’t know if this makes any sense but there are not many things to try.

                      You need to ask the factory how as it might depend on your build and Paolo recently saw your machine.

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                          Is said machine in the UK? do you still own the machine?

                            Jony No, machines are in Spain. Mine was sold but it’s nearby, I really hope it could be solved as this is a great machine.

                                tocateclas @Jony tocateclas @jony could ride back with that on his shoulders :)

                                Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

                                    DavecUK i have both machines, my brother bought the vesuvius @tocateclas then i’m intetesting to resolve the problem in both machines, let me know the way to test canceling this hx valve, Paolo can you send video or the steps to block the valve?

                                      DavecUK Correct me please if I’m wrong. I do not have the machine so I can not take a look inside. About how the HX works: there is the solenoid on the right side of the machine, the one I changed. This valve is letting the water to pass through the hx but there is no valve in the other end of the steam boiler? Am I right? In this case the hx would be always full of water? Then it can expand when heated and push in some place the brew circuit causing the issue? If this was the case I’m quite confident in this is what happens in these machines.

                                      It seems to have an easy fix then, just hope this was the cause.

                                          tocateclas Then it can expand when heated and push in some place the brew circuit causing the issue? If this was the case I’m quite confident in this is what happens in these machines.

                                          No, this won’t be happening, during a shot everything is open if HX is on and that hydraulic pressure caused by heating water becomes a non-issue, it also causes no pump back pressure.

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                                              DavecUK Thank you. Sorry for my English… I meant if this hx has some contact with the brew circuit when hx is off.

                                                  tocateclas I meant if this hx has some contact with the brew circuit when hx is off.

                                                  You need to read my earlier post about the theory of what might be happening because I am sure you have misunderstood it.

                                                  I am not concerned about any leakage to the sealed brew circuit as such in the way you mean…I’m worried about the pump trying to overcome Hydraulic pressure due to water expansion behind a non return valve.

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                                                    9 days later

                                                    Can anyone with this machine tell me what their is like as I think I’m loosing it.

                                                    I am under impression the steam boiler pressure drops lower and recovers much slower during steaming than it used to. I had it set at 125c and recently found I had to increase to 127c which is still not whatnot should be.

                                                    I flush and wait for it to come back to 127c before starting to steam. Only 160ml milk in the pitcher.
                                                    It falls to 122c before you notice it starting to recover although you can hear the boiler kick in around 125c.

                                                    I hope it’s just my mind playing games but I am convinced it wasn’t like that.

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                                                      prezes Check your advanced settings because it sounds as if the steamboiler is behaving more like a PID control than on/off control. You need to set the PID parameters for the steamboiler to behave like an/off controller.

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