Zodiaco Group Thermosiphon Limiter Configuration - Page 2

A haven dedicated to manual espresso machine aficionados.
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dominico (original poster)
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#11: Post by dominico (original poster) »

It is! I'm looking forward to vberch's analysis after he experiments with it this weekend. It will much more scientific than mine. I already found that I have had to flush to restart the thermosiphon a few times this week, and I think my tinkering with the thermosiphon may have had an affect on my results due to it stopping a few times without my realizing it. Still, I did successfully wind up with a warmer group and a cooler group, both of temperatures I am happy with, even though I took a frustratingly fumbling approach to get there.
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dominico (original poster)
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#12: Post by dominico (original poster) »

Posting a little update here:
I noticed my espresso had gotten a bit hotter over the last two weeks. Now, I am a rather bright and intelligent guy, but even I have an off-day every now and then and was originally thinking that it had to do with the water level in the boiler. Then I came back to my senses and realized that the ambient temperature of the room is at fault. We are keeping the room itself quite a bit warmer now than we used to, making the groups less effective heat sinks. So I restricted the thermosiphon on my "cool" group a bit more to compensate, almost closing it off.
It now takes even longer to get hot enough to make coffee.
The thermosiphon is prone to stop siphoning when the machine is allowed to cool and then turned back on, or after pulling shots with longer preinfusions, prompting the need for a short flush every now and then to kickstart the siphon back in gear.
Shot volume is greatly reduced.

I have been thinking over the reasoning for the last one, and since the shot water is fed by the thermosiphon it stands to reason that a restricted flow would reduce the overall volume of the shot. I am going to have to open the preinfusion valve all the way and hope that compensates for it, or install an air conditioner in that room a few months early...
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Il caffè è un piacere, se non è buono che piacere è?

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vberch
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#13: Post by vberch »

Good stuff, Dominick!

I was able to adjust the valve only a little bit, around 1/16th of a turn since unscrewing it more would allow the water to escape from the valve. What did you do to adjust yours? Did you install a second or thicker seal?

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dominico (original poster)
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#14: Post by dominico (original poster) »

On one of my groups I have over half a turn before it starts to leak, on the other I have about a quarter turn before it starts leaking. I was thinking of picking up some thread sealer or trying teflon tape to allow more adjustment without leaks.
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zeb
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#15: Post by zeb »

The leaks are because the setting is not a setting.

Vlad, don't you have the drawing I made about why this isn't a setting ? Can't find it again anymore...

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dominico (original poster)
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#16: Post by dominico (original poster) »

What do you mean by it not being a setting?

The temperature difference between my two groups is quite apparent when I rotate one "closed" vs leaving the other "open", so it is certainly having some effect.
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Il caffè è un piacere, se non è buono che piacere è?

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zeb
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#17: Post by zeb »

I'm sure there is a difference but it comes from elsewhere.

I'll try to explain later, as I miss English words, with drawing or/and pictures it will be easier.

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dominico (original poster)
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#18: Post by dominico (original poster) »

I'm looking forward to it. I want to learn all about this group that there is to learn. If you know of any resources, even non-English resources, I would be eager to read them. I have been looking for some sort of service manual in Italian for this group for a while, with no success.
https://bit.ly/3N1bhPR
Il caffè è un piacere, se non è buono che piacere è?

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