ECM flow control installation - Page 6

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Nunas
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#51: Post by Nunas »

This has happened to a bunch of us :lol: . The culprit is the sleeve bottoming out atop the mushroom, which prevents closing the needle valve all the way. Loosen the knob, turn the control all the way shut then lift the knob/sleeve off and reposition it on the spline as you wish, then tighten the knob.

dsc106

#52: Post by dsc106 »

Thanks, Nunas! Ok, now I can get 0g/sec when fully closed (no flow). But I have a new issue now...maybe it's just part of the design?

The control does not seem granular enough during the first 1/4 of a turn. My flow numbers are:
  • 1/16 = 3.5g/sec
    1/8 = 4.15g/sec
    1/4 = 5g/sec
    1/2 = 7.3g/sec
    3/4 = 9.3g/sec
    1 = 11.2g/sec (comparable to my stock flow of 10.9g/sec)
    1+1/4 = 12.65g/sec
    1+1/2 = 14.85g/sec
This doesn't seem like as ideal of a curve as showed @ 3:18 in the video - http://www.youtube.com/watch?v=P1Vz7aa_KtI - it seems most of the fine tuned control as shown in the video is between 1g/sec and 7.5g/sec, right where I suspect you'd want it most. But my current setup seems to race through the majority of that, giving me most of my control between 5g/sec-11g/sec range, and very little in that first 1/4 turn.

Any ideas why I am getting so much flow right out the gate, and not a more gradual increase?

If it matters, I am plumbed in @ about 2bar line pressure, and I did not install the stiffer lower grouphead spring, I am still using the stock spring down low.

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Nunas
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#53: Post by Nunas »

Any ideas why I am getting so much flow right out the gate, and not a more gradual increase?
Yes. It's a rather rudimentary needle valve :wink: In any case, the water debit isn't terribly important. With a loaded portafilter, the control will work fine. Since you're using the stock spring, at the beginning of the pull, the FC will be used to determine the length of the e61's inbuilt preinfusion time. Once that's over (about 4-bar), the control can smoothly change the brewing pressure.

dsc106

#54: Post by dsc106 »

Nunas wrote:Yes. It's a rather rudimentary needle valve :wink:
I see, ok, so normal? Any idea how/why WLL has a better curve in their video with the same device/machine?
Nunas wrote:Since you're using the stock spring, at the beginning of the pull, the FC will be used to determine the length of the e61's inbuilt preinfusion time. Once that's over (about 4-bar), the control can smoothly change the brewing pressure.
Apologies if I am missing something obvious... I don't understand what you mean by this. If I am using the stock spring but 100% engaging the brew lever (not partially), what would the FCD have to do with the e61s inbuilt pre-infusion time? I thought line pressure pre-infusion only ever occurred if I lifted the handle halfway, without engaging the pump?

Also, I re-read Jrising's post again, where he says "I would suggest taking the drain valve and spring completely out and leaving the bottom of the valve body empty down there." - what is the difference between:

(A) stock spring
(B) no spring
(C) stiff spring

I realize these questions seem to be exposing my lack of knowledge about how, precisely, the brewhead actually works! I'm a little lost.

Thanks so much for your time and walking me through this - I really appreciate it!

Pressino

#55: Post by Pressino »

dsc106 wrote:...
Apologies if I am missing something obvious... I don't understand what you mean by this. If I am using the stock spring but 100% engaging the brew lever (not partially), what would the FCD have to do with the e61s inbuilt pre-infusion time? I thought line pressure pre-infusion only ever occurred if I lifted the handle halfway, without engaging the pump?

Also, I re-read Jrising's post again, where he says "I would suggest taking the drain valve and spring completely out and leaving the bottom of the valve body empty down there." - what is the difference between:

(A) stock spring
(B) no spring
(C) stiff spring

I realize these questions seem to be exposing my lack of knowledge about how, precisely, the brewhead actually works! I'm a little lost.Thanks so much for your time and walking me through this - I really appreciate it!
The way the E61 group works is fairly simple, but there does seem to be a bit of confusion about what exactly occurs when the brew lever is lifted and the pump engages. As mentioned previously, there are a couple of techniques folks have come up with to "pre-infuse" the coffee before it is subjected to full brewing pressure, including briefly activating the pump, then shutting it off for a few seconds, then turning it back on to complete extraction. Valente actually designed the E61 so that when the lever is lifted and the pump activated there would be a short period of "pre-infusion" before the brew chamber ramped up full brew pressure. This is referred to as automatic preinfusion. Inspection of the original E61 patent drawing shows how this occurs.

There is a discussion of this here on HB.com. Poster #6 hits the point I want to make about the lower chamber "pre-infusion"spring:

Preinfusion on the E61 - revisited

Folks should review that thread and pay close attention to the design of the E61.

The original E61 spring was set to open at about 1.5 to 2.5 bar pressure, allowing the lower chamber to fill, at which point the brew chamber would ramp up to "full" brew pressure, which would depend on pump pressure and other parameters (such as the gicleur orifice size and pressure differentials in the other chambers (e.g. #3 and #14) of the E61.

Folks need to understand that the stiffer spring supplied with the FCD does not completely remove automatic preinfusion. What it does do is delay the onset of opening of the lower chamber until a pressure higher than the originally designed opening pressure is reached (on my machine with the stiffer spring that pressure was about 4bar). After the chamber fills you have full brew pressure over the puck, but with the installed FCD you can vary the pressure during the remaining extraction by adjusting the needle valve.
But since the new spring supplied with the FCD is much stiffer, you will lose the ability to run a classic E61 pre-infusion if you install it. If you want that ability, leave the stock spring in place. Your FCD will still work, but there will be some offset in the profile settings.

Pressino

#56: Post by Pressino »

dsc106 wrote:- what is the difference between:

(A) stock spring
(B) no spring
(C) stiff spring
/quote]

I forgot your question about "no spring."

If you remove it the lower chamber will beginning filling immediately when the pump is activated, probably shortening the time it takes for the brew chamber to reach full brew pressure. Not sure what benefit that would have...except maybe it means you could control the pressure of extraction entirely via the needle valve in the FCD. Not sure that's a good thing.

Also, we haven't discussed a form of passive rather than automatic pre-infusion in which the lever is raised to the point that hot water is allowed to enter chamber 14 but before the pump is engaged. That requires fine fiddling with the lever cam microswitch position. That's an entirely different discussion.

Nunas
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#57: Post by Nunas »

Apologies if I am missing something obvious... I don't understand what you mean by this. If I am using the stock spring but 100% engaging the brew lever (not partially), what would the FCD have to do with the e61s inbuilt pre-infusion time? I thought line pressure pre-infusion only ever occurred if I lifted the handle halfway, without engaging the pump?
I think Nick has covered it well. I'd add only that the inbuilt preinfusion time on the e61 (ie, automatic, not plumbed preinfusing by cracking the lever open above mid position), is controlled by two main things. The strength of the preinfusion spring and the flow rate. In a normal e61, the flow rate is fixed, set by the jet (gicleur). With the FC installed, you can slow the flow rate down as much as you want. This will increase the time that it takes for preinfusion pressure to mount. With the FC just cracked open 1/8 or 1/4, you'll see the preinfusion pressure very slowly increasing, after which time the pressure will rise more rapidly to full brewing pressure. On the other hand, if you open the FC fully, it will happen in the blink of an eye. Now, if you put in the stronger spring that comes with the latter kits the inbuilt automatic predinfusion is inhibited and you ride the control to set the pressure manually with the FC throughout the pull.

As for your no-spring question, I've never messed with that. My understanding of it is that instead of adding a stronger spring, which will accelerate wear on the cam, one can remove the spring and achieve a similar effect, but which will not increase the wear. Actually, I guess it should reduce the wear somewhat.

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Nunas
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#58: Post by Nunas »

Ben, I just ran a test to give you some actual numbers. On my Synchronika with the stock e61 spring and a blind basket, with the FC open 1/4 turn it took 22 seconds for the pressure to rise to 8 bar. At 1/2 open it takes 8 seconds, at 3/4 open 4 seconds and a one turn open 3 seconds. At wide open, there's a squeaky whooshing sound and the pressure rises nearly instantly. I've not run the test with the FC kit spring as I'm not sure where I put the darned thing. Maybe someone with it installed could run a similar test. Frankly, though, it boils down to personal preference. I tried both springs and liked the stock spring better. It gives the ability to set the FC in one spot and leave it, so that the preinfusion takes a specific amount of time followed by the extraction. With the FC kit spring, I felt compelled to ride the control.

dsc106

#59: Post by dsc106 »

Thanks so much! Ok, I am going to spend some time deep diving all of this and reviewing it. In the meantime, could I ask one more question outside the realm of the mechanics of the brewhead - an example of the practical difference in use? If you did the same profile side by side on no spring, stock spring, stiff spring - what would the difference be in operation? IE:

Stock spring: pre-infuse for 16 seconds, ramp up (??)
Stiff spring: pre-infuse for 12 seconds, ramp up (??)
No spring: ?

That sort of thing. I need to go review all of these links and re-read your posts, but if I am understanding all of this correctly, the softer spring creates an offset because water needs to fill the lower chamber first (and can due to the softer spring), so you have to wait longer before ramping to full pressure. Which may mean you add a few seconds to the start of a listed profile. Whereas a stiffer spring immediately hits the puck, but then when pressure hits 4 bar, only at that point fills the lower chamber... which essentialy results in a more immediate start to the selected profile?

Thank you again! I will do my homework in the meantime :D

Pressino

#60: Post by Pressino »

And here's very good explanation of how so-called "wetting" pre-infusion with the pump off works compared to the automatic built in pre-infusion:

http://coffeetime.wikidot.com/e61-pre-infusion

Very clear and I highly recommend it for those who are interested in this subject. :)