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  • Gaggia Baby Class Portafilter issue

    Hi there, not many posts under my belt so forgive my relative innocence! We recently bought a 2008 built Gaggia Baby Class online (had previously bought a Carezza some months earlier but the steam function packed it in) and had to replace the group head seal as a matter of urgency. My son bought a blank disc for back-flushing and we did that methodically prior to first use. The problem we now have is that the seal 'pops' as the group head heats up until it is no longer possible to insert the portafilter in the machine! I measured the replacement seal to make sure it was the correct thickness (8.5 mm) and that checked out fine, it is the seal with the rounded edges on one of the sides and that was the side inserted into the machine, second time round I reversed it and same result. Bought another seal on-line from a different supplier and basically the issue remains unchanged, exactly the same issue. When the machine is cool you can insert the portafilter but as soon as you've pulled a couple of shots it becomes unworkable.
    A couple of observations: each time the seal had been replaced there is evidence of water sitting in the groove, I wonder if there is an escape of pressure through the side of the shower holding plate that forces water/steam behind the group seal? Has anyone had a similar problem? Any insight at all would be most welcome....

    cheers, Ian

  • #2
    Originally posted by Porkchop View Post
    A couple of observations: each time the seal had been replaced there is evidence of water sitting in the groove, I wonder if there is an escape of pressure through the side of the shower holding plate that forces water/steam behind the group seal? Has anyone had a similar problem? Any insight at all would be most welcome.... cheers, Ian
    Hello Ian, I don't have a Baby Class, nor have I ever used one, but I have rebuilt a couple of Classics, and dismantled a Carezza for parts, so I'm familiar with them. I'm not sure if the Baby's have a three-way solenoid valve like the Classic, a pressure valve like the Carezza.

    It does sound as though water may be getting under the seal. It should not be able to get behind the seal while the portafilter is locked in tight, but maybe it could be happening as the portafiler is removed.

    If there is any damage to the flange in the group head that the inner edge of the seal fits against, or if the inside diameter of the seal is too big and it doesn't fit firmly against the flange, it could let water in.

    However, I think that there would have to be at least some pressure in the group as the portafilter was being removed, to force water under the seal. Do you hear any release of pressure as you turn the handle to remove it ??. If you do, then a faulty solenoid or valve may well be the cause of your problem, but if not, I'm not sure what else it would be.

    There is a forum at Gaggia Users Group who are very experienced and helpful with all the small Gaggia models, you could try posting your query there.

    Comment


    • #3
      Thanks for your insights deejee, I don't seem to hear any pressure release when the portafilter is being removed, I know that if I left the portafilter in for too long with the Carezza after pulling a shot it seemed to be quite hard to remove and the pressure was evident but not with the Baby. The group head appears in excellent shape and the seals both appear to have been regulation size and fit so it is certainly hard to imagine how it is possible for the seal to build pressure and force itself out of the housing. I'm just a little wary when a couple of parameters are altered at once (in this case the seal replacement AND the backflushing) as my experience is that it makes it difficult to know exactly which one is the culprit. I'll swing by the Gaggia Users Group as recommended and see if there's any info to glean....

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      • #4
        Still trying to get some traction on this issue with the Baby Class. I've got a 3rd replacement group seal on order (not that much choice here in Tas) and am not convinced that it will make any difference anyway. Tried sourcing info from Gaggiausers but even they are at a bit of a loss as to why we have water being trapped behind the seal, the fault is nothing if not consistent: turn the machine on, prime the boiler, wait the requisite among of time before pulling a shot, perfect 25 sec shot and crema etc, pull a 2nd shot ditto, then the water expands behind the seal pushing it out and thereby blocking the PF from full insertion. When the machine cools the water obviously contracts allowing the PF to insert normally. The group head appears to be in pristine condition, we've thoroughly cleaned the shower distribution disc and screen etc, replaced the seal after removing water from groove in group head etc etc but still the problem returns to haunt us! I am quite convinced that there is not an issue with the seal itself as we have replaced it with ones from different suppliers with zero change in terms of the problem described. Bummer is that we have had to damage the seal each time we remove it as it has had a number of cycles of compression and heating and cooling, I don't particularly mind shelling out $10 each time for a new one (apart from the week-long wait for the postie to deliver it) if it had any effect on the issue. Is it possible for the PF/basket to be subjected to an excess of pressure and if so could that inject steam or heated water up behind the group seal, another words is there a valve or something similar malfunctioning?

        Comment


        • #5
          Hello Ian, Sorry to hear you are still having problems.

          I don't have a solution, but I do have a couple of questions.

          Are you using pressurized or non-pressurized baskets ??

          What does the top of the puck look like - firm and dry-ish or wet and sloppy ??

          Have you tried leaving the portafilter in place for a while before removing it ??

          Once this problem starts, how long is it until the portafilter will lock back in place again - a couple of hours, overnight or not until you remove the seal ??

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          • #6
            Thanks for responding deegee, I'm using non-pressurised baskets (had the "perfect crema" disc with the Carezza but didn't use it on either machine-wanted to go 'authentico'). The puck, well it is "moist" but not too much standing water when the shot's been pulled, probaly about right for one of these machines if I'm not mistaken. As far as leaving the PF in place goes, my son pulled a shot this morning and when I got up to take him to work (yes 7.00 am on Sunday!) He couldn't actually remove the PF having left it in for only the normal 30 secs or so. I managed to remove the PF using quite a bit of force, much more so than would otherwise be necessary normally. The puck was very dry which I guess is to be expected. We usually don't bother trying to reinsert the PF until the next morning by which time the machine has well and truly cooled down but having said that we have sometimes reinserted it later in the day when the demand for coffee has been at a crescendo, perhaps 2-3 hours later. Generally every time a shot is pulled it seems to add more water in behind the seal so the situation deteriorates and eventually the PF will not insert no matter what, only by puling the seal out can we start again. Any thoughts on the issue very gratefully appreciated!

            Comment


            • #7
              OK, if you're not using pressurised baskets, we cant blame them, and if the puck is just moist, then the 3way solenoid is probably working, so I'm running out of ideas. I found some specs that says the Baby Class has a 15 bar pump, which is lower than many other espresso machines, so I don't know where any excess pressures could be coming from.

              I have a couple of ideas that could be worth trying. The first is simply to put some lube on the bearing surfaces of the portafilter lugs and crank the handle in as tight as reasonably possible to create a better seal between the gasket and the group head to see if that will keep the water from getting in behind the gasket.

              The second is a bit more radical. If we cant stop the water getting in behind the seal maybe we could provide a way of letting it out. I can't remember where, but I once saw a picture of a seal that had some small slots around the outer circumference of the seal. They were not very wide or deep - from memory (very vague), they were only one or two mm wide and deep. I think there were four of them, but I'm even less sure about that. I had no idea at the time why they were there, but they might have provided a pathway for water to escape between the outer edge of the seal and group head flange it seats against. They should not have any effect on the normal sealing between the basket/gasket/group, but might provide an exit for the water, the next time the P/F is locked in.

              So if all else fails, maybe you could try cutting or filing a few shallow "V" or "U" shaped notches in the outer edge of the gasket.

              Comment


              • #8
                Sorry for delayed response on this one (had a succession of guests staying since xmas and haven't been able to check the forum) and thanks for the detailed information. We can certainly give the first suggestion regarding the lube a try after pulling the seal and getting rid of the water again, I'm starting to run out of seals that aren't somewhat compromised by the removal process but it's worth a shot. I tend to try not to tighten beyond 6 o'clock normally as it is already quite firm being a new full-thickness gasket but I'm running out of options! In terms of the pressure, if the basket (and seal) are normally meant to be pressurised to 9 bar when a shot is pulled and which is dictated by the pressure limiting valve OPV(?) placed after the pump then is it not possible that a defective valve could load the basket with a few bars more?

                I've seen the gaskets you're referring to
                Click image for larger version

Name:	notched group seal.jpg
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ID:	738407: Interestingly the supplier contends that it has "4 grooves in side wall for easier removal and replacement" but I can imagine that they might performs as vents to release the pressure. I guess the detective in me wants to find a logical reason for the water getting behind the seal in the first place as it can't be considered normal. I replaced the seals in the Carezza we had including the boiler to group head etc and the machine performed faultlessly so I don't believe it's "operator error" but I'll do anything possible to get this machine functioning properly...
                Last edited by Porkchop; 21 January 2015, 09:26 AM. Reason: Commercial link(s) removed

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                • #9
                  Originally posted by Porkchop View Post
                  In terms of the pressure, if the basket (and seal) are normally meant to be pressurised to 9 bar when a shot is pulled and which is dictated by the pressure limiting valve OPV(?) placed after the pump then is it not possible that a defective valve could load the basket with a few bars more?
                  The Baby has a pressure valve which I think it is different to the Classic's OPV, but even if it was faulty I don't think it would cause your problem. I'm not certain of this, but I used a Classic for a while with a jammed OPV, so it was running at full pump pressure - probably about 15/16 bars. I also used another for a short time which which ran at about 13 bars before I adjusted the OPV . Neither of these had a problem like yours.

                  Originally posted by Porkchop View Post
                  I guess the detective in me wants to find a logical reason for the water getting behind the seal in the first place as it can't be considered normal.
                  Yes - Me Too !! My main suspect at the moment is not the pressure valve, it's the three way solenoid valve.

                  Which leads me to ask a couple more questions. When you back-flushed it did the water/suds flow into the drip tray ??.
                  Do you see or hear any discharge into the drip tray at the end of each shot ?.

                  You mentioned in a previous post that your son had a problem removing the P/F ( after leaving it on for a little longer than usual ?) when he had pulled a shot.
                  Does it always unlock more easily if you take it off sooner, than when you leave it on for while ?.

                  Have you removed the shower screen and the shower block and cleaned them ?.

                  To be honest, I am not sure if the answers will be conclusive, but they might get us closer to the source of the problem.

                  P.S. I also wonder how/why you damage the seals to remove them. I can usually get them in or out fairly easily when they are new and fairly flexible. It's only when they are old and brittle that I have to damage them to get them out. I use smallish blunt screwdriver, (no sharp edges) and a bit of vaseline or soap to get it down the side of the seal to prise it out.
                  Last edited by deegee; 21 January 2015, 10:49 AM. Reason: See P.S.

                  Comment


                  • #10
                    The reason I mention the OPV is that a certain US-based supplier who shall remain nameless due to forum T&C has stated on their site that post-2006 Babies are not to be recommended due to inferior internal components, I believe that the valve in question is made of plastic on our machine whereas one can 'mod' it with an adjustable more robust brass version from the Classic. I guess that without testing pressure at the basket with a jury-rigged gauge one would never know what is taking place, it's of comfort to hear that you have experienced higher pressure at the basket without any issues so that probably rules it out...

                    I actually have thought it may be the solenoid valve all along too but the answer to the question is it appearing to function normally is a "yes"! When back-flushing the water/suds discharge as per regulation into the drip-tray. We've taken the cover off the drip-tray both when back-flushing AND pulling shots to check its operation and both appear to be working correctly. We have removed the shower screen and shower block and cleaned them meticulously (right from the get-go) I've even substituted the shower block from the Carezza whilst we still had both machines and there was zero difference.

                    The day that my son had difficulties removing when PF (which apparently was very shortly after pulling the shot) I think can be attributed to using the machine successively over a couple of days without removing the group seal and attendant trapped water.

                    As far as removing the group seals, I understand what you are getting at in terms of damage to the seal but the group head is chromed brass if I'm not mistaken, and I would rather damage the edge (external) of the seal than risk scoring or gouging the soft brass which is absolutely unmarred at this stage. The seal fits so tightly within the groove (which may perhaps be due to hydraulic pressure) that it is extremely difficult to get any kind of instrument down the side far enough to prise it out, again it's not really a normal situation unfortunately. The seals are relatively cheap at $10 with postage but a group head is considerably more expensive but point taken, I'm a tightwad don't worry!

                    Comment


                    • #11
                      Well that seems to eliminate a couple of theories, so what's left ?.

                      I guess high pressures could still be a factor, even though I never had your problem while using classics with OPV's that were jammed or set too high. The machines are similar, but not identical, so I suppose it's still a possibility.

                      I have been wondering about gasket sizes, because I once got one off FleaBay that was too big. Both the OD and ID were about 1.5mm larger than what seems to be the "correct" size of 72 X 56 mm. Though there is some doubt about this - I have seen various combinations of ID's from 55 to 57 and OD's from 70 to 73.5 mm.

                      My theory, FWIW, is that the fit between the inside of the seal and the inner flange is important, and the fit between the outer edge of the seal and the outside of the groove is less so. Thus a seal that was bit undersize should be better than one that was a bit over. Then I found the same thread on the Gaggia forum that you did, and the only person who has the same problem is using an undersize gasket !!. WTH

                      I also found a site that had pics of a lot of different gaskets and quite a few had three or four slots around the outer edge as in the pic above. Have you had a chance to try this idea yet ??. If one of your seals is damaged around the outer edge, you might as well mutilate it a bit more.

                      I also keep thinking that if the three-way is working, the only way that water would get behind the seal is if the P/F is not locked in tight enough before & during the shot. Have you tried some lube on the lugs yet ?.
                      Last edited by deegee; 22 January 2015, 10:09 AM. Reason: Typo's

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                      • #12
                        Yes the elimination process continues unabated deegee! We took the machine apart yesterday and dismantled the solenoid to ensure that it was both operational and clean. I had seen one stripped down on-line from the same machine which had split internally but our's appears in perfect shape, the various components had no build up of scale, they moved freely etc. Electro-mechanically it would also appear to be functioning correctly as described in a previous post above.

                        We took the group seal out yet again, attempted the small blunt screwdriver technique aided by food-grade grease and was able to gingerly remove it, excess water was cleared, group head cleaned meticulously and everything put back together again. The one thing we didn't do was try the grease on the PF lugs approach before pulling a couple of shots, and of course we ended up with the usual scenario! It might have been because we were in a lather to video the machine whilst in operation to document the fault as it occurs. I'm probably boring the pants off everyone on this forum (who are actually reading this topic) but here they are for people to make their own mind up...btw they are very short! If you think I'm completely incompetent I had to create a Vimeo account, upload all the videos to it after compressing with HandBrake and then upload them finally to coffesnobs. The videos were taken by my son in short clips as the process was spread out over quite a while, the next three in sequence follow in the following post according to site rules...
                        Last edited by Porkchop; 23 January 2015, 02:10 PM. Reason: add links

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                        • #13
                          Hhhhmmmmm......try again?


                          Java "Link? What link?" phile
                          Toys! I must have new toys!!!

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                          • #14
                            Originally posted by Porkchop View Post
                            We took the group seal out yet again, attempted the small blunt screwdriver technique aided by food-grade grease and was able to gingerly remove it, excess water was cleared, group head cleaned meticulously and everything put back together again. The one thing we didn't do was try the grease on the PF lugs approach before pulling a couple of shots, and of course we ended up with the usual scenario!
                            Partly because I have no other ideas left, and partly because I think it's got to be worth trying, I would really like to see you try a combination of slots in the outer edge of the gasket, grease on the P/F lugs, and the handle locked in good and tight. Is one of your earlier gaskets OK around the inner half of the top & bottom faces and the inner edge which sits against the flange ?. That should work well enough to test the theory without chopping into your only good one.

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                            • #15
                              And (hopefully) here are the remaining clips:

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