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Low-end HX or High-end single boiler?

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  • #16
    Re: Low-end HX or High-end single boiler?

    Hi Dennis,

    Come visit!

    Id be delighted to assist and will ensure that you leave only with the right machine for you and your budget....

    Chris

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    • #17
      Re: Low-end HX or High-end single boiler?

      Let me echo Chriss input. While my upgraditis has run rampant a number of times ;D, Chris has always been a valuable information resource with no pressure to buy, buy, buy, that I could discern.

      Greg

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      • #18
        Hi all,

        First, the reason I'm reigniting this ancient thread rather than posting anew is that I realised I was one of those long time forum lurkers that occasionally asks for advice and then never reverts with the outcome of their research.

        Sorry.

        I did end up finding a deal on a Diadema Perfetta and Rocky doserless from a local cafe/roaster and have had five years drinking great shots, even getting my partner back into coffee (from weak lattes to now using the double basket) and toddlers who can comment on my tamping technique and know the real meaning of "don't touch that - it's hot".

        Until......

        ...and this is the other more selfish reason for posting...


        ...last week I got back from a week away and found switching on the machine trips the safety switch. I reset a few times and then managed to make a normal espresso (machine runs slightly hot of late but that's another issue).

        The next day I am unable to use the machine without tripping the safety switch at all. Reading other CS posts I look to the low water microswitch, and yes the machine turns on fine when the heating element is off but then trips as soon as I depress the switch. I've had others recently use the machine and leave it in strange states (lever up, machine off, steam heating on etc) and suspected water damage from tank overfill or heating element damage from lack of boiler priming. The microswitch was quite rusted but I used a mulitmeter (mothballed since switching from a corretto to a Behmor) to confirm continuity - so the switch is fine.

        The guts seemed quite clean but there was some water stains/rust at the bottom. Taking off the bottom grill and the covers on the element terminals revealed the picture below.

        As you can see one terminal is badly corroded while the other is clean as a whistle. Has anyone seen this before? It's been a long time since high school chemistry but the fact it's one and not the other terminal seems to imply a fuel cell-type oxidation rather than water damage (no?). A compromised heating element? The multimeter confirmed there is still continuity between the two element terminals, and strangely I was able to make a normal hot coffee that initial time after the problems began so the element isn't completely blown.

        Any help would be much appreciated. Hopefully it can still be salvaged with a fix/service etc.

        (And this time I'll update on the outcome!)

        Cheers,
        Dennis
        Attached Files

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        • #19
          Hi Dennis,

          Chances are that when the element warms, it becomes porous. Most likely it's had it.

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          • #20
            I would start by cleaning the terminal and the screw post back to shiny metal and see how it goes before you panic. It is possible that the corrosion has increased the resistance so the current draw has increased enough to trip the circuit breaker. I'd look into some anti corrosion treatment. I think Inox makes something.

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            • #21
              Looks suspiciously like the outer casing of the element is porous as Chris mentioned above. Seems as though the water is finding its way through to the terminal via the element insulation compound. Don't think that is all corrosion but mostly staining from the water at the bottom of the boiler...

              Mal.

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              • #22
                Hi Dennis,

                In my humble experience as a sparky, if RCD trips, fault more often than not in an appliance with a heating element.

                Note: RCD/safety switch detects faults, circuit breaker detects overload of circuit - 2 different things.

                More than likely heating element causing the problem. Replace the element with new and it'll be as good as gold.

                Cheers
                Dan

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                • #23
                  Thanks everyone for all the quick responses so far. Yep, evidence stacking up for a dead (ish) boiler element. Think you're right, Dan, as the surge protection board wasn't shutting off but the safety switch at the board (ground faults right?).

                  And water finding it's way down through the element makes sense as well, as the machine would have to be submerged in two inches of water for the terminal to get that wet.

                  Is element replacement a straightforward procedure? I assume it can be removed through that same open panel.

                  Cheers everyone.
                  Dennis

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                  • #24
                    Update: I'm back, and now at an appropriate brewing temp!

                    Picked up the Perfetta from Talk Coffee on the weekend, and despite the apparent corrosion on the boiler element terminal, it was actually the thermostat that was failing. The machine had been getting hotter and hotter lately and I had been "managing" it by turning it off for a few minutes while grinding etc.

                    So, a new thermostat, service on the lever and temp calibration, and the machine is now singing better than it ever has (thanks Chris!). Someone even gave the exterior a good polish!

                    In that few weeks without home espresso (I broke my Presso in the first week, no doubt trying to get to 9 bars with plastic internals) I had many moments of weakness, and it's a miracle I don't currently have a Bezzera Strega-sized hole in my wallet. I'm now really glad I didn't pull the trigger, as the reduced temp has a vastly different (improved) set of characteristics in the cup, and now it's back to changing existing variables in the form of grind, dose, tamp, roast length and even perhaps grinder upgrade (from a Rocky) before I move onto shinier machines. Bought a couple of EP Precision baskets and have ordered the Cafelat naked PF from CS.

                    And I'm prepared for my partner to keep rolling her eyes the way she does when I show her youtube clips of naked PF pours and other coffee p0rn!

                    Dennis

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                    • #25
                      Congratulations on your machine working again, unfortunately, you'll have to find another reason for a shiny new one.

                      Comment


                      • #26
                        Our pleasure Den78. Thanks for the kind words!

                        Our tech Phil does amazing work and I am thrilled you're happy. I'll pass your comments onto him.

                        Your machine is now running as it should have when you purchased it. Hopefully, it should keep upgraditis at bay for a little longer.

                        Cheers

                        Chris

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