I am using a stainless steel Cafelat XT portafilter with my BZ10. Although the diameter of the PF is 58 mm like the E61 compatible one, the lugs on the BZ stock portafilter have a different orientation than those on an E61, so the PF I have is the CMA/Astoria version. Since the lugs are thicker than on the stock portafilter, the only group gasket that fits is a Bezzera 8 mm rubber O ring (I have also tried a silicone 8 mm gasket, but it doesn’t allow the PF to seat properly and so far I haven’t found any other silicone one that fits). I can source the rubber O ring, but it doesn’t last longer than 2-3 months tops, which I think is very short. I was wondering if this quick wear of the rubber gasket could be caused by frequent chemical backflushing, which I typically do once every fortnight?

BTW When backflushing with the detergent, I follow the procedure that DaveC has shown on his YT videos, which is pause for 30 seconds in between the first 3-4 pump cycles to allow the detergent to do its cleaning work.

    BertNL Backflushing won’t shorten the life of the O ring, heat does though. The Bezzera BZ10 has a heated group and if that gets hotter than a normal HX, it could shorted the group gaskets life. As will leaving the machine on 24 hours per day.

    Can I ask how you know the O ring has worn out/ end of life after 2 to 3 months?

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      Also after a brief research tells me the o-ring for the bz10 is 9mm (rather than 8mm) - so must be that the shape is different.

      @BlackCatCoffee will know.

        Hi Dave and Medium RoastSteam, thanks for your reply.

        I think the shape of the O ring is indeed the reason why other gaskets do not seem to fit. When newly installed, it will seal without me having to lock it in very firmly. I use the stock PF with the blind disc for backflushing and although that one can be inserted as far as the 5’o clock position, with either PF, the gasket will seal well with a relatively loose fit. After some time (maybe 1.5-2 months) of use, however, it will start dripping a bit of water from the rim, so I do need to lock it in more tightly. At this stage, I inspect the gasket and if still usable, I put it back in with a sheen of Molycot along the outer surface. Once it starts leaking again, I often find the rubber has become brittle and when I bend the O ring, it snaps. This typically happens within 3 months after I have installed it new.

        I must say that I regularly do leave the machine on for most of the day (say from 7.00 till 22.00) when I am working from home and during weekends. I typically make espressos in the morning and one after supper and use the hot water tap for tea in between.

        I will see if restricting the use of the BZ10 to morning hours only makes a difference; I can use a kettle with Brita-filtered water for tea and use my Robot for my evening espresso.

          MediumRoastSteam

          The original BZ gasket is one of 9.3 mm thickness with a beveled outer circumference. That one has a very tight lock-in even with the stock PF when it is new, but I can’t possibly use it with the XT portafilter. The silicone one I tried is the one from Cafelat for CMA/Astoria groups, 72×56×8 mm. It fits into the grouphead, but the PF will not seat.

            BertNL good information given, certainly sounds like the gasket is perishing. 1.5 to 2 months is a very short life indeed. I never evaluated a BZ10 but it’s possible the gasket might be very near the group heater.

            If I were designing such a machine a function to put the group into low temp standby would have been considered, so it can be ready for use in minutes, but if unused, would drop the temp by 20 or 30C. If this is something they have done, it would be worth using it.

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              As I have understood, by EU regulation these days all electric appliances including espresso machines are required to have a standby (or automatic power-off) function, so the more recent version of the BZ10 (at least for the EU market) probably has this implemented. My machine is 9 years old and does not. I agree a standby function on the grouphead heater that just reduces the group temperature would be a useful feature. It is less weighty than an E61 and would bot take much time to be woken up, especially when (after assuring that the boiler is upto temperature) you run a blank shot with the PF in place.