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Lelit PL042EMI - on a mission!

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  • Lelit PL042EMI - on a mission!

    inspired by my possibly unnecessary pump replacement (maybe it was a simple pressure lock that opening the steam valve could have remedied, but too late, i'm not putting the "spare" back in), and having noted the crack in the group head rim, i bravely invested in a new part, and some gaskets, and ultimately even some silicone grease, and set to it

    there was instruction with photos on the interweb for what appeared to be a very similar model, but of course, being an italian design, that didn't mean it was the same - i should have realised what i was in for when i read "Use the 15mm/17mm (it varies) spanner to undo the split nut holding in the shaft, then remove the nut."

    still, i learned to build and then overclock computers almost 2 decades ago, and they aren't reliably the same between generations or even brands of motherboard, so what could possibly go wrong ?

    armed with some trusty tools, i was off on an adventure

    off with the top, and a look at the top of the boiler - what a work of art (and by art i mean akin to abstract modernism with wires) ?

    Click image for larger version  Name:	DSC00043.jpg Views:	82 Size:	300.6 ** ID:	924607

    the group head had previously been replaced (due to the same damage from poor design leaving it vulnerable to shearing the lip if the portafilter is tightened too far), and conveniently, the connections had been marked for reattachment

    this was the (recurrent) injury to the group head :

    Click image for larger version  Name:	DSC00064.jpg Views:	49 Size:	54.5 ** ID:	924609

    and thankfully, for the current replacement, lelit appear to have recognised their engineering mistake and substituted a new design that omits the rebate on the side, making the edge a continuous ring of metal with the rebate confined to the inner part, as shown below on the left, versus the old part on the right

    Click image for larger version  Name:	DSC00062.jpg Views:	48 Size:	225.0 ** ID:	924611


    sadly they don't appear to be ashamed enough to offer a recall on the defective design part ? , even though they have eventually remedied a recurrent weakness

    presumably my ability to repeat the prior damage will be lessened; that and changing the group gasket when i notice a leak, rather than attempting to push the handle anticlockwise without any regard for potential catastrophe


    still, if they had made it more robust i would never have had the impetus to become an espresso mechanic-in-training, so there's that... ?

    so, a question for those who have deconstructed a boiler - how to clean the inside effectively while i have the chance, noting i am leaving the coil in situ, because i have already detached enough pieces for the replacement grouphead to be fitted, but i am still obsessive enough to wish to make the older part of the boiler more akin to new

    it's pretty grubby, and it may have been that way for a very long time, but still, i'd rather it was less "distressed":

    Click image for larger version  Name:	DSC00063.jpg Views:	49 Size:	193.6 ** ID:	924608

    so, let's have some suggestions that don't involve too much effort for return on investment, nor exotic chemicals or equipment


    only one more day in the weekend, and these bits still need to be returned to their original home

    Click image for larger version  Name:	DSC00056.jpg Views:	48 Size:	277.7 ** ID:	924610

    anyway, thanks for joining me on my journey of discovery; it was less traumatic than i presumed, and i feel i am now capable of undertaking any other repairs

    and more importantly, to service the machine a bit more diligently ☕
    Last edited by Javaphile; 15 August 2022, 09:24 AM. Reason: Commercial link removed

  • #2
    Vinegar does a pretty good job as a descaling agent. You can probably immerse that whole part on vinegar watered down with water (warm will speed things up) for a few hours or overnight then clean with an old toothbrush/scrubbing brush and green scourer.

    If you have activated descaling powder this will work even better.

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    • #3
      I don't think there is much to worry about, can't see any scale, just the usual coppery discolouration which is harmless anyway.

      Mal.

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      • #4
        there's some white crud on the wall at the 9 o'clock position in the photo, but i wonder if it could be silicon grease from a previous gasket installation (although it would need to be floated up from inside the seal- not impossible i guess, as there is crust inwards of the prior seal which might be remnants of that potential source)

        i'll check it during daylight, and poke it a bit

        meanwhile i've procured some scourers to buff the brass where the new gasket has to seat, to make the mating surface smoother



        i'm enjoying the restoration, and have polished the outer casing while the (removed) protruding parts are out of the way

        it's going to look pretty fresh, and with the new components likely work somewhat better too

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        • #5
          well, after some further observation and some thinking, i decided to go for a 50/50 white vinegar / boiling water soak, after blocking the necessary holes with soft foam and using some silicon tube for the other vent as shown, and "filled 'er up"

          Click image for larger version

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          the initial soak revealed that the crud was staying put; there was a definite tide mark from the clean

          Click image for larger version

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          and so, for completeness, after a thorough rinse, i inverted the boiler into an appropriate container, and repeated the process, and...

          Click image for larger version

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          the coil looks pristine, and i should have softened up the stuff where the gasket seats enough that an attack of the scourer will make it perfect

          i attacked the white stuff seen in the photo above with a dental probe, and it chips off like... boiler plaque ! so maybe it is scale - but i would have expected the vinegar to move it along

          any ideas?

          i am keen to put all the bits back together in daylight, because my eyes like that more than directional led blueness

          Comment


          • #6
            well, hit the white thingies with a dental probe and a tiny file end (the flat bit, not the teeth) and they all chipped off like small crusty bits of shell, so calcium seems to be the cause

            put all the parts back together and primed the boiler, and was greeted with a small geyser at the apex where the steam outlet emanates; no electrocution from the local wiring, and switched off and grabbed the trusty shifting spanner, because the hex on the fitting was 11mm and of course like the steam wand fitting, inconveniently didn't correspond to any of my available spanners

            screwed it down tight and dang! it seems to work like it should

            pulled a few practice shots to season the rebuild, and then a very passable double shot with good crema that tasted rather good (better than the interim delonghi managed, so it's promising of great things once i dial it in)

            next step, consider a new basket, because the rims on my (old) collection are rather flat, and although they make an adequate seal (with a push) i suspect that the lack of a convex profile on the rim are creating a less than optimal seal arrangement which was likely part of the issue that had me try too hard and break the old group head

            buy hey! colour me a rocket scientist - we have lift off !!

            Click image for larger version  Name:	DSC00072.jpg Views:	0 Size:	238.2 ** ID:	924763

            next : weighing the dose like a real investigator, and make the effort even more worthwhile

            Comment


            • #7
              today's improvement was the investment is a pair of new double shot baskets (@ $14 apiece), as the rim on the old ones was so flat that the seal required the rotation that had caused the group head to fracture

              end results? crema like the good old days, and a 13gm double shot that lingers on the palate for ages - mmmmmm....oily ! the shot when pulled is >50% crema initially


              the lovely people at jetblack also test drove a better spring in the portafilter (i am sick of having to retrieve the basket from the knock box), but in the end a bit of tweaking of the old spring was a much happier result for my needs - as demonstrated on the spot during my shopping expedition

              a huge vote of recommendation to jetblack for making my journey to better coffee an easy path

              edit : they also confirmed that "old faithful" is now at least a decade in use, based on the fact that it was originally purchased when they were based in cremorne - with new group head and pump, and the well cleaned boiler using new seals for the parts, it's essentially a "new" machine for the parts that actually do the work

              Last edited by scruffy1; 16 August 2022, 07:58 PM.

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