A Potential Future Mod For Lelit Elizabeth

JHCCoffee

For the next while, I will be focusing on learning to use the Lelit Elizabeth, to improve shot taste and consistency.

After that, I might think about a “pressure profiling mod” or alternatively a “flow profiling mod” … If… the preceding will work with (not interfere with) the programming of the machine. Or otherwise adversely affect it.

For example, I effectively used a rheostat connected to the electrical input of my Breville DuoPro pump to control pre-infusion ramp up and shot ramp down.

What about flow control valves? Has this mod been done? What in the way of aftermarket parts/kits are out there? Would this work on a Lelit Elizabeth? Is it A good idea?

Other mod ideas?

Don’t shoot the writer on this. Just musing.

JHCCoffee

DavecUK

JHCCoffee The Elizabeth uses what’s called a ring group, they are solenoid controlled for water entry and venting. This makes a flow control valve impractical. You certainly could use a simply pwm dimmer on the vibration pump which would allow some control from 6 to 9 or 10 bar…much below 6 bar, the pressure drops away suddenly. A more sophisticated frequency controller could be used, which would give a wider range of control.

There is not a huge amount of space in Elizabeth, so it would probably have to be an external control box, something manufacturers don’t generally like to do….I suspect Lelit would say buy a Bianca…😉

JHCCoffee

Just while we are on the topic, out of curiosity, hypothetically, what frequency control device would you get (specs/brand/model) and where how/where would you wire it in? It would need to be very easy to control, while pulling a shot. Like with some kind of a knob or slider, if feasible.

DavecUK

JHCCoffee I’m not sure, perhaps other people with more knowledge of Freq controllers will chime in.

JHCCoffee

DavecUK

Here is an interesting thread. Pressure Profiling Controllers

Any comments/thoughts on it? Best approach?

DavecUK

JHCCoffee I remember looking through it…I think there are some interesting ideas to try perhaps.

JHCCoffee

@DavecUK and all.

A Lelit E owner on Facebook told me that he has installed a 200w single pole dimmer dial, wired in sequence to the vibe pump power in (hot) wire. He says it works well, and that he can control pressure in 1 BAR increments from 1 to 9 BAR (his OPV max). This apparently allows him to do flow profiling. He says that he has not lost any other Lelit E functionality and that the machine continues to work well (after one year).

Does this ring true? Are there any downsides?

Alternatively, as per the preceding HB link, might I better consider installing a:

Variac?
High speed PWM (Khz)?
synthesized, lower frequency, ½ AC cycle sine wave controller?
Low speed, unsyncronized PMW (10s of Hz)?

I would love to be able to do flow profiling, which is why I’ve come back to this topic.

I unfortunately cannot afford a new Lelit Bianca at this time, especially as I will be buying another NZ for the cottage. Buying both would not sit well with my wife, who enjoys Keurig coffee and cannot understand my espresso hobby affliction (“Its just coffee!”).

Or maybe I could find a used lever machine, if we could give up more counter space, which would not sit well with my better half.

Or should I just forget the whole ☕️🐇🕳️ thing.

Sigh 😮‍💨 … Its a rough espresso life 😁

Just musing 🤔💭

DavecUK

JHCCoffee My experience of this without using more sophisticated circuits is:

Some pressure control from 9 bar down to 6 or 7 bar…but after 6 it simply drops away.

If you saw the experimental blue 🔵 Minima I had, the control box was quite large. However with more sophisticated circuits I could control both flow rate and pressure of the vibe pump exactly like a decent. With all the same odd sounds of the Decent.

If course complex profiles done manually, is like drawing a circle on an etch a sketch in 27s. Simpler ones were quite doable though.

I may dust it off next year for fun…

JHCCoffee

hornbyben I modified my Rancilio Silvia to give accurate pressure control, but this was done with an advanced microprocessor (see the link in my signature if you’re interested). This can hold the pressure at a set point of your choosing, but it controls the pump using phase angle control (turning off the power part way through the AC cycle) that gives much more precise control than dimming, it’s got a pressure sensor for real-time feedback, and it uses a proportional-integral controller to keep making real time adjustments. The power versus pressure curve also isn’t linear. I suspect the Decent is using a similar control approach.

hornbyben DavecUK

Do you think that this approach would work on a Lelit E? Any risks, in terms of functionality or parts life impacts?

What about using a Hi Frequency PWM (Pulse Width Modulation)? Good or bad idea? Any risks, in terms of functionality or parts life impacts?

Similarly, any risks in using a simple dimmer mod?

hornbyben

@JHCCoffee, You can definitely gain flow control by dimming the power to a vibe pump, but please don’t think it’ll be a case of set the dial at position X and it will hold Y pressure, because it’s not that simple. Dimming only controls how hard the pump pushes. How this translates to pressure and flow will depend on the resistance of the coffee puck, and that varies. If you have a pressure gauge and keep adjusting throughout the shot you might be able to get reasonable control, but it definitely won’t be set and forget.

I modified my Rancilio Silvia to give accurate pressure control, but this was done with an advanced microprocessor (see the link in my signature if you’re interested). This can hold the pressure at a set point of your choosing, but it controls the pump using phase angle control (turning off the power part way through the AC cycle) that gives much more precise control than dimming, it’s got a pressure sensor for real-time feedback, and it uses a proportional-integral controller to keep making real time adjustments. The power versus pressure curve also isn’t linear. I suspect the Decent is using a similar control approach.

A dimmer mod is pretty cheap and easy to reverse, so as long as you have enough understanding of electricity to make sure you don’t electrocute yourself, why not give it a go and see how you find it.

hornbyben

JHCCoffee unfortunately I haven’t used a lelit e and have no idea of the wiring diagram, so can’t really advise they’re. Although assuming you’re only affecting the power to the pump you should be pretty safe. Loads of people have done this on single boilers like the Gaggia or Silvia with no issues, and vibe pumps are pretty cheap anyway.

DavecUK

hornbyben Not the specific Lelit quiet one. Olab sell a quiet pump but it’s not the same one they make for Lelit.

To answer the OPs question…yes it should work OK.

JHCCoffee

DavecUK Not the specific Lelit quiet one. Olab sell a quiet pump but it’s not the same one they make for Lelit.

I went onto a Facebook electronics forum, for advice on PWM specs and settings. They asked: How is the pump driven currently? What voltage, frequency & pulse shape, current requirement?

If I can answer these question, then I can get the right PWM, which I sense will be better than using a dimmer (that stalls the pimp below 6 BAR). Fyi, my Lelit E is built for North American voltage/current (110V AC).

Yes, this is a rabbit hole, but I’m deep into it; not even my back rabbit feet are sticking out 🐰🐇🐰

JHCCoffee

@hornbyben @DavecUK

Thanks Horbyben!

My Lelit E has advanced microprocessors, and firmware that they periodically upgrade, linked to programable buttons and displays. I am uncertain as to whether and how the Ito or other controllers would integrate with the Lelit E. I suspect that the Ito would not integrate well. Moreover it may not be a good idea to (or I may not like to) eliminate the Lelit E controls, and just use an external controller for all functions.

Thoughts on this?

@hornbyben I also have a whole bunch of questions on Dimmers and PWMs, that I can message you about, if you have interest and time to reply. Let me know.

hornbyben

JHCCoffee I agree that I’m not sure something like the Ito would integrate well. It’s definitely better suited to a dumb machine.

A dimmer could still be with a go through. It’s just providing resistance to the live going to the pump, so unless the power is going somewhere after the pump (unlikely as for safety the switch is usually on the live), then it should be pretty safe.

I’m happy to continue the conversation but it’s probably best if it’s done on here so others can chip in. I’m an enthusiastic amateur but by no means an expert.

JHCCoffee

Shall do. For anyone that will have patience with me, here are my numerous questions, that will help me and others thinking about this type of mod:

Will a PWM will allow me to better control flow than a dimmer?
How would a PWM affect the performance and life expectancy of the Lelit E pump? I do not wish to damage it or reduce its life.
If I buy a PWM, should it be low or high frequency? What frequency?
What other specifications should the PWM have?
How should it be set, if the settings can or should be changed?
What specific PWM should I buy? Make? Model?
If I didn’t buy a PWM, what type dimmer or rheostat or potentiometer or vario should I buy? I have read of people buying and trying 6 different dimmers, before finding one that worked. I just need something that works.

hornbyben

JHCCoffee Sorry JHC, this is outside my knowledge. The ones I’ve seen online tend to use a cheap variable resistance type dimmer. I did have a look around, and found a post on home barista that stated:

Variac - works well
High speed PWM (Khz)- works well
synthesized, lower frequency, ½ AC cycle sine wave - don’t know, why bother
Dimmer - most people report OK
Low speed, unsyncronized PMW (10s of Hz) - works poorly

I can’t verify this is true, but thought I’d share in case it’s useful.

Good luck

JHCCoffee

hornbyben

Most appreciated, Hornbyben! Thank-you!

Saw that as well on HB, and have both posted and PMd some folks there. We’ll see if we receive a response.

@DavecUK I would like to contact the manufacturer of the vibratory pump that is contained in the Lelit E, to obtain their thoughts on how to best incrementally control water flow from their pump. Might you share the name of the pump manufacturer and the pump model name/#? Feel free to PM me if you wish.

CoyoteOldMan

JHCCoffee the name of the pump manufacturer

Olab - https://www.olabitaly.com/ (there is a link to their catalogue right on the home page; I have no idea what model the ‘quiet’ one is, and it may not even be in the catalogue, as it’s made to Lelit’s specs)

DavecUK

JHCCoffee All the information you have been given is correct, including the fact that the Olab Silent Pump is absolutely not the same as Olabs Lelit version silent pump.

More than this I cannot say, as I received all the specifications and details of how it’s quiet, but was asked to never share the information.

Inspector

If it is the same one used in mara X then it should be this one below.

CoyoteOldMan

JHCCoffee Well… the picture Inspector posted above gives a few clues, and the description on the Olab site provides others https://www.olabitaly.com/products/fluid-control/self-priming-vibration-pumps/serie-k09541l_111.html

Note - this is NOT the Lelit pump, but it’s the standard Olab ‘silent’ model. Whether the difference is just the addition of a second rubber suspension pad or there are other differences to the electrical and mechanical parts is an open question.

Voltage, frequency and pulse shape are ‘as provided by mains voltage’ i.e. for US/Canada 120V 60Hz full sinewave. The pump (as per Olab description) includes an integrated rectifier which feeds only the ‘positive’ half of the sinewave to the coil. There is no indication of the characteristics of this rectifier, or of the mechanical circuit in the pump (which is likely to be the limiting factor in terms of frequency response).