I posted about this before...but here it goes again.
On my machine an Izzo Alex Duetto IV Plus with the Profitec flow control kit installed. This is the one that has a range of 2 1/4 turns from full OFF/CLOSED to full OPEN. And at full OFF/CLOSED it has zero (no flow) flow, there is no dripping at all, hence OFF/CLOSED.
My machine's original max flow at 9 bar was ~12.5 ml/s with the stock mushroom.
I have set (and this is arbitrary depending on where you position your handle/knob after closing the valve completely so there is no flow when the machine's lever is pulled up) the handle to be positioned at 12 o'clock when the valve is off/closed.
2 1/4 turns counterclockwise from that position opens up the valve completely. The handle ends up pointing at 9 o'clock at that point.
I did measure the flow after installing the Flow control kit.
1) OFF/12 o'clock position .......no flow
2) 6 o'clock position/half a turn counterclockwise.......~3.7 ml/s
3) 3 o'clock position/3/4 turn counterclockwise.........~5.7 ml/s
4) 12 o'clock position/one full turn counterclockwise...~7.3 ml/s
5) 9 o'clock position/1 and 1/4 turns counterclockwise....~9.3 ml/s
6) 6 o'clock position/1 and 1/2 turns counterclockwise......~12.5 ml/s
7) 9 o'clock position/2 and 1/4 turns counterclockwise......~37 ml/s Note: This is at the position where the valve is fully OPEN

So 1 and 1/2 turns is the range from fully closed/off (no flow) to 12.5 ml/s flow, which was my original/stock max flow of my machine with the stock mushroom and brew pressure/pump set to 9 bar.

The Lelit flow kit has a max flow at open of ~6.3 ml/s (position where the paddle hits the machine and will not turn anymore). On my machine that point would be at about 2 o'clock position/ half way between 3/4 and 1 full turn counterclockwise from the 12 o'clock OFF position (or ~315 degrees counterclockwise from the OFF/CLOSED position).

I have used the blind basket to do backflushings and have noticed the same that the pressure will move past 9 bar on the brew gauge. I expect this because again I'm using the blind basket. It will never do this during an extraction because there will be flow through the puck and into the cup. I have not experimented if this pressure creep above the set machine's brew pressure happens at all points in the turning range.

I have pulled shots at the two turns counterclockwise position from OFF/CLOSED (have not measured the exact flow at this specific point in the range but I'm guessing it is somewhere around 30 ml/s??) and they have been very good and no they have not been gushers, they flowed into the cup normally. Actually at this "flow point" I have to grind a little coarser so that the extraction flows into the cup at a more normal pace. I think it is because at that high flow rate the puck presents a much higher resistance to the high flow and actually the flow rate into the cup slows down. I have noticed that the flow rate is actually faster into the cup when I set the flow rate at a lower setting, and again I believe because the puck resistance changes according to the flow rate onto it and into it. I have noticed also, when profiling (and I do this only from the 2 o'clock 315 degree position in the range), that when I turn the handle clockwise to a lower flow/pressure the actual flow that I see into the cup increases/gets faster not slower. So even though I am decreasing the flow into the puck by closing the valve I believe more water is getting through because the puck is offering less resistance or because at that point the puck has eroded some due to the extraction of compounds and therefore now it presents less resistance than it did at the start.

I don't mind having all these higher flow points in the range since I will often pull shots without profiling at set points above the 315 degree position.
If I do want to profile I will usually set the handle at no more than 3/4 turns counterclockwise from OFF/CLOSED and then move the handle clockwise to manipulate the extraction.

I did find something really neat...if I set the handle at somewhere between 1/4 and 1/2 a turn counterclockwise from OFF/CLOSED to 1/2 a turn counterclockwise from OFF/CLOSED (6 o'clock) I see a sort of lever kind of action. As I start the shot the pressure will slowly ramp up and then reach the max set pressure and then I will see the needle on the brew gauge slowly moving counterclockwise down to a lower pressure by itself as the extraction progresses (I'm not touching the handle), similar to a lever profile or a manual profile using the handle but in this case it is being done automatically with no user/barista participation. Again I've notice this on my machine but I don't see why this would be different in others.

And all of the above is just my experience on my machine, with my coffee beans, at my location YMMV.

Nunas, you say yours turns from OFF/CLOSED to Open in 1 3/4 turns but you also say that at closed you get 2.68 ml/s flow????? You should be able to set it so that at CLOSED you get zero flow and it is truly closed. I wonder if your 1 3/4 turns at full open gives you 37 ml/s flow like the 2 1/4 turns full open does for me. On your valve kit it seems like it requires now half a turn less rotation because you stated that you get 7.14 ml/s at 180 degrees or half a turn and I get ~7.3 ml/s ( so basically the same) but at one full turn and you get 11.7 ml/s at 360 degrees or one full turn and I get ~12.3-12.5 ml/s at 1 1/2 turns, again half a turn less. But this with your CLOSED setting giving you 2.68 ml/s flow and my CLOSED/OFF setting giving me 0 ml/s flow.
I'm thinking I rather have 2 1/4 turns from CLOSED/OFF to fully OPEN since it would make it less sensitive in the manual profiling range which is 315 degrees from CLOSED (~6.3 ml/s to 0 ml/s) vs whatever it is (~180 degrees) with the valve you have that has a 1 3/4 turn range since any small handle movement clockwise will be a larger jump/difference in the flow or pressure.

Nunas, you say yours turns from OFF/CLOSED to Open in 1 3/4 turns but you also say that at closed you get 2.68 ml/s flow?????

Correct; this was a surprise to me, as I thought the needle would seat and shut the flow off totally.

As for your analysis about how much of a turn makes a given difference in flow, also agree. Even though our two controls seems to be somewhat different, at some points in their range they agree (even if the angle is different). I don't know about 1-3/4 vs 2-1/2 turns. I originally thought that the Bianca control, which I understand does not turn through a full 360-degrees, might be the way to go. But, I'm warming up to the idea of a greater range, (either yours at 2+ or mine at 2-), especially if WLL and their suppliers come up with a reasonable knob that keeps us from burning our fingers and that would be easy to grasp and turn.

I'm still scratching my head about how at some settings the brew pressure can be more than the pump pressure, if left long enough in a blind basket. It's analogous to getting an extra couple of volts out of a battery...not possible. Clearly, as a retired EET, I understand electricity better than the flow of liquids

The Bianca control does not turn 360 degrees only because the paddle touching the machine's front part of the case impedes it. If you take the wood paddle off you can turn the valve further, so it is an artificially limited range, change the paddle or somehow raise it above the front of the machine (I've read about some users that have done this to the Lelit Kit) and you will get more turning range and a greater max or even a full open valve.
The difference between yours and mine is probably that I can close mine fully with 0 ml/s flow and you say you can't close off yours fully and you get 2.86 ml/s flow and you only have a 1 3/4 turn range which is half a turn less range than what I have.But the difference in the flow you get at some points compared to what I get at approximately the same point is about that 2.68 ml/s flow difference (because you can't start from fully OFF and 0 ml/s flow like I can).

The pressure builds up when using a blind basket because the flow into the basket has no place to go and the hot water expands so the pressure builds up above what the pump is set and to the max pressure level set for the OPV to come into play (open) which should be somewhere around 12 bar I would guess.

Luckily with my machine the original long knob/handle turns un-impeded throughout it's full range like it can be seen on the photos I posted earlier on this thread, so no chance of burnt fingers, unless I'm really clumsy and touch the sleeve.

Thanks to Aldo, I now know that there is an adjustment on the Synchronika Flow Control. Those reading this thread may recall that his kit turned over two turns, while mine turned less than two. Also, his fully shut off the flow, while mine did not. It turns out that the stainless sleeve that holds the knob is splined to the shaft and is held in place by the knob screw. Oddly, even though I had the knob off, I did not notice this. So, if you have one of these kits and wish to have zero flow at fully clockwise, just loosen the knob, screw the control CW until it stops, then tighten the knob. Also, you can loosen the knob, pull the sleeve off, and reinstall it in any position you wish. Too bad this thing didn't come with instructions!

Mine did?..

Kelly, can you post the instructions here? Mine was just a plastic bag with the part inside...no instructions of any sort. I'm guessing that others might benefit from having the instructions.

Nunas wrote:Good news! I've also directed my comments to WLL. Today I heard back from the. They and Profitec/ECM understand the issue and are working on a third knob design. I'll be getting a free one, and I assume so will other previous buyers. While it is easy to be critical of this small debacle, it is great to see a company stand behind their products. Also, good to see a company that listens to their customers. My fingers are crossed that 'the third time's the charm'

Any indication on when this "Version 3" will be available? The ECM with flow control was out of stock for a couple weeks on WLL, so I thought that might be for a retool. But they came back in a few days ago, and it doesn't look like anything is different. I'm in the market for a machine, but I'd like to buy the final version.

I'm in the market for a machine, but I'd like to buy the final version.

As far as I know, you're safe to buy the ECM/Profitec machine any time, as the flow control kit is an optional add-on kit, which anyone with a wrench can install in 10-minutes or less. This is unlike the Bianca, which only has one flavour...with the flow control. I've come to terms with the crummy little round knob on my Synchronika (numerous minor finger scorches is excellent training ).

I'm not in a huuuuge hurry, so was hoping I could wait to get the final product with everything professionally installed and calibrated. But I might get impatient if it starts taking too long and go that route

Nunas wrote:I'm still scratching my head about how at some settings the brew pressure can be more than the pump pressure, if left long enough in a blind basket. It's analogous to getting an extra couple of volts out of a battery...not possible. Clearly, as a retired EET, I understand electricity better than the flow of liquids

It's just physics, old knowledge keeps being forgotten. It's all because water expands during heating. It's why all machines have an expansion valve confusingly called the OPV by many.

http://coffeetime.wikidot.com/pressure- ... g-pressure