Puck pattern after extraction

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Marigold70

#1: Post by Marigold70 »

Anybody seen such pattern, see image?
Round middle area, pretty smooth, surrounded by 5 holes (machine lelit 57 mm) is not imprint of the screw, as the distance to the grind is large enough. The holes appear as channeling, always at the same place. No channeling in other areas. The 5 holes seem to originate from the 5 bore holes in the plate above the shower. I have no technical explanation. Espresso appearance and taste great. Any idea?


ojt

#2: Post by ojt »

I have seen these cavities on the Pavoni often. The main reasons have been either a clogged dirty showerscreen or a high pressure water jet from between the piston and the water inlet hole. Of course the latter would not happen on your machine but something similar maybe.

I think quite a few pump machine users have replaced original showerscreens with "precision" screen from for example IMS, those might help distribute the water better. Another solution is to use either a puck screen (like this one from BPlus) or simply a disc of coffee filter paper cut to measure.
Osku

Marigold70 (original poster)

#3: Post by Marigold70 (original poster) »

Hi ojt, good information, will come back to you later :!:

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cafeIKE
Supporter ❤

#4: Post by cafeIKE »

Marigold70 wrote:The holes appear as channeling, always at the same place.
In a bottomless portafilter, you see channeling in the same place?

Is the pf removed from the group at the end of the shot or has it sat in the group for a while. If the latter, could be drainage or leakage from the spreader. A photo of a shot in progress, the shower screen and spreader might shine a light...

BTW, Lelit makes a SL of machines. What model is yours?

Marigold70 (original poster)

#5: Post by Marigold70 (original poster) »

Ojt: precision filter / puck screen are no "straight" solutions, it should be possible to find reasons first.

cafeIKE: sounds good, I must admit I was too lazy to make photos with bottomless pf as you suggest. Would actually be the fastest way :( Pf removed fast or stay in place, same phenomenon. The puck is well pressed and dry.

BUT: right now I watched and realized during flushing, there are 5 (!) streams of CLEAN water coming out from the screen, of course without pressure. I always clean and wipe it after each shot. Have not done backflushing yet or unscrew the screen to see. BTW what is the spreader?

The machine is lelit pl02temd, very new.

Nunas
Supporter ♡

#6: Post by Nunas »

Marigold70 wrote:<snip>BTW what is the spreader? The machine is lelit pl02temd, very new.
I've not seen this model of LeLit. In any case, in most espresso machines, certainly all e61 boxes, there's a flat brass nut above the shower screen. It has a slot to unscrew it. That's the spreader. Its function is to divert the brewing water stream from vertical to horizontal and divide it into multiple streams.

Marigold70 (original poster)

#7: Post by Marigold70 (original poster) »

Thanks Nunas, I have the explosion drawing and will check.

Sorry i made mistake, the machine is PL42TEMD, not pl02... :)

ojt

#8: Post by ojt »

Marigold70 wrote:Ojt: precision filter / puck screen are no "straight" solutions, it should be possible to find reasons first.
I did mention dirty showerscreen as one potential cause :) And I didn't say precision filter, but showerscreen. The puck screen and paper filters are great mitigating measures for dirty showerscreen, among other potential benefits.

Question is though, did you experience this issue right from the start or just lately, or did you only pay attention to the puck later. I'm guessing the machine itself does not have an issue.
Osku

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Jake_G
Team HB

#9: Post by Jake_G »

One potential fix for these types of issues is to simply rotate the shower screen.

I'm not sure if the diffusion block looks exactly like part MC191 below, but regardless it seems that some of the jets are making it right through some of the holes in the shower screen.


Photo courtesy of 1st-line


If you look at the back side of the shower screen and the holes on the block, chances are that you can rotate the shower screen just a little bit to have solid metal between each of the jets and your puck. It's not ideal to have a shower screen pattern that can align with these jets, but it's also not uncommon. I'd crack the shower screen loose a bit and rotate little by little until you don't see the jets when you flush water through the group. Then tighten the screw and verify.

Cheers!

- Jake
LMWDP #704

Marigold70 (original poster)

#10: Post by Marigold70 (original poster) »

Sorry ojt for mistaking precision shower for filter!

I have been watching this for some time now, after having fixed to it more and more, so I don't remember since when. I now finally unscrewed the screen to see "the secret" behind. The 6 (not 5) spots below the water holes are very clean, the rest area just "coffee dark" but NOT clogged or oily, so could simply wipe it with a cloth.

It looks that my pattern is systemic and always was there. It is just the matter of water distribution, as there are no mechanical components in between which might be the issue. I only wonder that no lelit user responded to my topic.

Now Jake - yes this is the drawing of my machine. I understand what you mean. Don't you think there would never be solid metal below the jets, because there will always be some holes in the screen below them, as the screen grid is much tighter than jets diameter? Or am I totally wrong?