Has anyone ever PID'd a lever machine?

[cannonfodder]

I got to thinking (that is a scary thing). My lever machine is essentially a single boiler espresso machine, like a Silvia. If I put a PID on the machine then I could set the boiler temp for brewing and prevent the group head overheating problem that plagues Pavoni type machines. If I have the boiler set at 205, then the group head will not exceed 205 no matter how many shots I pull. Then when I want to froth milk, I just up the temp on the PID, froth, and then set it back down. If it works well for other single boiler systems, why would it not work for a lever machine?

Are there any known issues, has anyone tried it?

[another_jim]

Couldn't resist.

[cannonfodder]

I was actually thinking of mounting it in the bottom of the machine. I would need the smallest PID I could find. I was thinking of removing the badge on the front center of the machine and mounting the display there. I wanted to keep it self contained, no parts sitting on a table or hanging off the machine.

[AndyS]

Couldn't resist.

Did you ever PID the Presso?

[another_jim]

Did you ever PID the Presso?

Yes I dip my hi precision pinky into the water, compute the error, and add the precise amount the water to keep it at 203.4F

[AndyS]

Yes I dip my hi precision pinky into the water, compute the error, and add the precise amount the water to keep it at 203.4F

I said PID, not DIP.

Would a PID-controlled immersion heater work in the Presso?

[lino]

I've got a LaPeppina that I PID'd also. Actually, they're all the rage, I hear...

Also put a brew pressure gauge on it. There are two thermocouples (T type). It's placed right at the turn to go down to the dispersion screen. There's also a brew pressure gauge. I'm most happy about the fact that the two in front are removable and the machine can be returned to stock (basically). Normally, there is a flat head screw there, just like the hex screw on the front of the E61 (same purpose too). The head sits in a counter bore, which happened to be just the right* diameter to thread 1/8 NPT... So if I remove the pipe tee and put the screw back, you can't tell the c'bore is threaded.

*Actually it's a little bit too big. I had to use a modified (ground down) pipe tap to use the larger part of the taper, and I had to cut about 3 threads or so off the male threads on the pipe tee.


The other TC is for the PID. The pocket/cup that it's put in is right above the inlet to the cylinder...

The PID box is the common Fuji 1/32 DIN.

It was a fun project, and it certainly makes the coffee more consistent.

Oh, and the brew pressure starts at 6 bar and drops to 3 by the end of the 2 oz shot.


ciao

lino

[cannonfodder]

I have a couple of metric OmegaLock fittings. I was thinking of drilling/tapping the bottom of the boiler and putting the fitting on the bottom. Then I could run a rigid 1/8 inch TC in it. That would allow me to get the sensor in the boiler as opposed to fixing it on the outside of the boiler. To many options, to little time and money.

With a Pavoni style machine, the water chamber is filled by means of the boiler pressure. If the water temp in the boiler is only 205, would there be adequate pressure to force the water up the feed tube into the grouphead?

[HB]

If the water temp in the boiler is only 205, would there be adequate pressure to force the water up the feed tube into the grouphead?

Recall that the boiler pressure gauge doesn't move until the water is boiling vigorously... no steam, no pressure.

[cannonfodder]

That was my concern. At my altitude I would guess that that the boiling point of water is in the 210 range. Ohio is relatively low. When my machine is at temp I get about .8-.9 bar. One bar is 253F, so I would guess I am running about 250F. I don't think I would be able to develop enough pressure to push the water up the brew water feed tube from the bottom of the boiler.

Owe, well. I guess I should just spend more time enhancing my skills and less on UberGeeking out my equipment to compensate for my shortcomings.

[oly_puller]

Dan - all -
What I don't understand reading this thread is if the boiler temp is around 250 or so to keep pressure up and thus move water out of the boiler to the group, how the heck can it be "controlled" to a comfortable 203 brew temp by the time it hits the puck? I feel like a little kid trying learn a different language and realizing that just learning a new alphabet isn't quite enough...

I've tried to dial in my machine by adjusting the pressure switch dial - lower pressure, lower temp. Evan at 53 feet above sea level, I've got no usable pressure if I have my machine backed off so the water coming out of the screen is around 206... so getting to 203 isn't going to happen.

I'm concluding that the water is cooled (even though it's devil hot) as it runs though the group head and all that brass... so... I think I finally get it when folks say the first few shots are good, but once the machine starts to get hot - game over. How do the rest of you lever folks keep your brew temp at 203 on the dot for say a nice back of Black Cat or something? Or do you really even stress about it?? I mean - is it really all just about taste? Ultimately yes, but then temp wouldn't be discussed at length so often... man... this is the Matrix! Why'd I take that red pill?

How would a PID help out in this case - I get that it controls the boiler but it couldn't keep the group from getting too hot. Do you have to surf the PID up to temp, then start backing it down for the next few shots... then crank it back up for steam? Wow...

Pt

[lino]

Hey,

I think part of the confusion here is due to the difference between LaPeppina and most other levers (Olympia, Elektra, Pavoni).

LaPeppina can be PIDd because boiler pressure is not used to drive water during its use. The system in the levers mentioned above requires steam pressure above the water to drive it up a tube and into the grouphead. That means to operate they must have a sealed boiler at a temperature somewhere above boiling.

Exactly as you mentioned, there is no need to PID that boiler because controlling that temperature is ineffective due to all the (needed) heat loss that occurs later as the brew water enters the group. Since the heat that water loses is dependant on a large number of variables, there is no need to start at a precise temperature.

One way that could be considered for PIDing such a machine is to modify the fill cap so that you could use a bicycle pump to pressurize the boiler. Then you could control the boiler temp as needed, and your new enemy would be figuring out how to minimize the heat lost in the brew head, or at least getting it to a steady state condition, so the loss was repeatable... All in all, I'd say it's not a project likely to meet with great success, and even if you do end up with good temp control, it'd still be a pain with the long warm up (since now the group must get hot) and a pump etc. Kinda defeats the purpose.

I have a Micro Cimbali lever that looks like a good candidate for PID also, but I need to figure out how to "revive" and protect the aluminum boiler... As well as making a few of the parts that were missing, like dispersion screen, among others...


ciao

lino

[oly_puller]

You know - I've been thinking about this for a while- or at least a good hour...

What someone needs to do is to figure out how to cool the group head externally on machines like these... really what we're talking about is letting the boiler do its thing - which is controlled by the pressurestat - that will cycle on and off so the pressure/temp is *fairly* constant - but what increases without intervention is the heat of the head. I'm thinking something like a peltier cooler or something...

I built a ccd camera for my telescope and it used a pump to circulate cooled water through the ccd camera heat exchanger chamber to keep the chip running at -15 degrees. If someone were to channel out the part of a E61 or wrap it in something like coiled copper tubing and then run cold water through it, I bet you could figure out how to dial in the cool water circulation so the screen temp of the water stayed right where you wanted it... hmmm...

This is just how Dr. Frankenstein got started... (it's Frankensteeen!)
Pt

[cannonfodder]

Lino explains it quite well. The type of machine I have is dependant on boiler pressure to force the water into the water chamber on the group head. If I PID it and run it at 205 (assuming some temp loss would give me 200-203 at the puck) there would be insufficient pressure to make the machine work.

I did see somewhere, someone did add a hand pump to the machine so they could run the temp at the proper level, but use the pump to pressurize the boiler to force the machine to work. They used air pressure instead of steam pressure.

It is just not worth all of the work for me. My machine is a complement to my pump machine. I use it at work in my office. I purchased it knowing about these issues, but since I only make one or two doubles at any one time, it was not that big of a concern. I just thought it would make a fun project.

[oly_puller]

Yep sorry to derail the thread... I get it now. Heck - with all this talk about PID'ing machines, you'd think the manufacturers would start including stuff like this on all sorts of machines - not just the really high end ones.
Love to hear an update if you decide to move forward with the project.

[mathias]

I've got a LaPeppina that I PID'd also. Actually, they're all the rage, I hear...

Also put a brew pressure gauge on it.

Oh, and the brew pressure starts at 6 bar and drops to 3 by the end of the 2 oz shot.

ciao

lino

Interesting stuff you share, thanks!

I am very surprised be the low pressure you read. Several people have indicated that the Peppina can make very good espresso. Often one reads that the pressure needs to be 8 bar or more. Do you know the accuracy of your pressure gauge?

[lino]

I am very surprised be the low pressure you read. Several people have indicated that the Peppina can make very good espresso. Often one reads that the pressure needs to be 8 bar or more. Do you know the accuracy of your pressure gauge?

La Peppina does make good espresso.

The gauge is a 2% FS rated gauge. That means the error should not be more than about 1/4 of a bar (or so)

I believe the number. The few [spring] lever machines that I've had my hands on all had springs that I have a very hard time believing can produce 8 bar. You can get very good espresso at less than 8 bar.

That said, if I "help" the lever on LaPeppina and watch the gauge and keep it near 9 bar, I like the espresso better.

ciao

lino

[another_jim]

That said, if I "help" the lever on LaPeppina and watch the gauge and keep it near 9 bar, I like the espresso better.

Tell me how ... please

[lino]

Hey Jim,

dunno how I missed that post for 3 whole days... Sorry.

I just lift the lever manually, assisting the spring.

One hand on the drip tray holding the machine down, one hand on the lever pushing it back up. One eye on the pressure gauge trying to keep it near 9 bar.

The lever is actuated with a direct mechanical linkage (crank arm type) so you can back drive it.

ciao

lino

[hbuchtel]

This is a little off subject, but I'm hoping the people following this thread will be able to answer this question-

I'm having a little trouble with how to ask this . . . so lets see . . .

Take a lever machine that depends on boiler pressure to force the water to the group head (such as Pavoni), and two different situations,

1. a full boiler 2. a boiler only 1/3, 1/4th full of water. Assume everything else is the same.

Ok, so say both have been boiling long enough to provide the necessary pressure to get the water up the the group head. Now, if you could measure the temperature of the water in the boiler, would they both be at the same temperature? Would the boiler with less water be at a lower temp then the full boiler (or the reverse?)

I'm having trouble wrapping my mind around this one, what do you all think?

-Henry