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?

Couldn't resist.

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.

another_jim wrote: Couldn't resist.

Did you ever PID the Presso?

AndyS wrote: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

another_jim wrote: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?

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

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?

cannonfodder wrote: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.

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.