Rob, I went through the same process/rationale you did with my G. Evol. After an initial 'getting to know you' period, I started cranking the Sirai PStat up by 360° rotations. (My initial pressure settings were Pmax= 1.07, Pmin= 0.83). Made coffee at each. Kept track of the min-max pressures according to the gauge. Went all the way to plus-four revolutions, which was Pmax= 1.2, Pmin= 0.96 bar as measured on my machine.

I did tended not like the way the machine behaved at the higher settings, or the espresso it made (though I figured out how to best use it after some experimenting). It took more flushing to get to a good brew temp the higher the Pstat setting. So I started turning the Pstat down, again by 1 screw revolution at a time. It was surprising to me how well the pressures going down matched those I measured going up.

On reaching the initial start setting, I continued on down to minus two revolutions of the Pstat screw. This got my machine to Pmax= 1.01 and Pmin= 0.80. This is lower than the factory setting, and I like it the way it is. The flushes are MORE than eric's "2 ounces", but noticeably less than they were at the Pmax setting of 1.2.

Moreover, I find pressure is STILL way above adequate for steaming milk - I can make nice microfoam in a short period of time - not timed, but I'd guess about 30s.

So I'm happy at -2 revolutions of the Pstat screw for right now.

FYI, I find Eric's Thermometer an invaluable aid in flushing my G.Evol. Only thing to keep in mind is there is a small but significant time lag in temp readout, and once you have that down, it's duck soup. Not trying to shill here, but I couldn't manage too well without it. I also used a Scace device which provided faster readings at the group exit point, as well as the actual temp delivered to the puck. Great for correlating the E61 thermometer readings and actual 'water on the puck' temps - but the general correlation of the E61 temps (in the brewhead) being about +3°F higher than that delivered to the puck are reasonably accurate.

To sum,
1) the Rocket factory setting may be set where it is (low) for a reason.
2) the lower pressure range settings seem to work better for whatever reason, and steam pressure is still way more than adequate.
3) being able to measure the temp above the brewhead during flush is very helpful for developing an effective flushing technique.

Finally, I suspect the pressure readings from any of these machines are not terribly accurate and have a pretty good ± between individual machines. However, for an individual machine, the pressure settings seem pretty repeatable.

If anyone would like a relative graph of Sirai Pstat pressures vs "± cranks of the screw" on a G.Evol. I could probably figure out how to post a jpg of my graph as an example.

It's a nice machine and can make really nice, and very consistent espresso.

Regards,

Al

fwiw, on HX machines which see minimal steam usage, I set 'em for .9 to 1.0. This pretty much removes brew water overtemp issues.

I have been having the same issues with my machine since I purchased it in April 2010. When it is first turned on in the morning it will pressure up to 1, stay there for a couple of shots, then the pressure will drop to zero.
Sometimes when pulling a shot or just running water through the brewhead the machine hesitates.

It has had new control board installed and now the distributor has told me that it needs a wiring upgrade. This is the communication I received: "We did just hear back from Rocket about the modification and fortunately it seems to be a relatively simple solution. There is one small wiring jumper we will have to make up and send out to you. But the rest is just changing the position on a couple of wires. I am attaching the instructions so you can look over the procedure. Let me know if you think you can handle it at home, if not, I can look into getting you out a shipping label to get the machine back in here."

I haven't heard back from them as yet as to the wiring jumper and I want to make sure if I do this wiring that my warranty is not voided. They have sent me a photo wiring diagram which I am assuming they received from Rocket The attachment is 840KB which is more than I can upload on this site so let me know if you'd to see it. I'll keep you posted here on what actually happens with the wiring jumper.

Hi there, I also own this machine. I bought earlier this year and I installed eric's thermo-adapter as well. I've tried adjusting both up and down. The problem with adjusting down is you only get one shot and then you have to wait a good 10 minutes for the temp to recover due to the restrictor. I currently run at 1.2 and even then my second shot is too cold unless I slow down my routine. I'm probably going to try running even hotter. Plus I find the steam a bit anemic at anything below 1.2

Here's what my routine look like...
(keep in mind actual brew temp is a few degrees below what erics' therm reports)

I flush until just after the temp peaks and begins to drop. Maybe 5-7 seconds? Then I grind, dose, tamp, and lock. Once I lift the brew lever the temp initially spikes at about 209 and then works it's way down to about 205 before I stop. This is with the boiler set to 1.2. Even if I take my time before brewing my next shot the temp will be about 6 degrees lower than the first shot. I'm considering removing the restrictor as I believe it's causing the machine to operate much differently than most of the machines owned by HB'ers. I'd rather have my machine work similar to most HB's so that trouble shooting is easier.