So it sounds like it is indeed possible for one of these gauges to under-read the actual pressure. Correct?

I say "yes", more than likely due to a loosening of one of the adjustment screws. The nice thing here is that Shawn can "brew" with a blind filter and compare the two gages as both should be equal under this condition.

Yes, that is the plan. Ordering a PF gauge kit from EP but some holiday is slowing it down!

My opinion of those PF's with attached gage is less than desirable (and I am being kind). Do you not own a thermofilter? I have the parts necessary to add a gage to it and would be SIMILAR to that shown below except that the gage would be remote and not attached to the thermofilter.

I'm not buying the one with the PF. I'm going for one of these:

http://www.espressoparts.com/V_512?&search_id=1972887

I bought the brass components, tape, and a gauge from home depot the other day, but the gauge just flooded and leaked and didn't work. Guess it was the wrong type of gauge for this application (it was only 3 or 4 bucks)

My LM portafilters have a 3/8 screw on the bottom when I disconnect the spout, so I don't need to use the thermofilter, but can if it turns out I need to. I'm just getting this gauge from EP to make sure its the type that will work for this purpose.

And my same comments apply.

erics wrote:My opinion of those PF's with attached gage is less than desirable (and I am being kind). Do you not own a thermofilter? I have the parts necessary to add a gage to it and would be SIMILAR to that shown below except that the gage would be remote and not attached to the thermofilter.

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The version I use, designed by Psyd and described in the thread I referenced, uses a quick-release coupler so the gauge can be removed from the thermofillter when not needed.

The version I use, designed by Psyd . . .

Absolutely . . . its great. He (Psyd) and I traded emails on this long ago and I have since improved my own using a short f x m x f "tee" and Swagelok fittings/tubing. You need to keep the surface area of the thermofilter and its modifications as close to the original as you can or your temperature readings CAN BE off.

I hope it will be less of a hassle to change out the boiler gauge than described in that gs3 thread. The internals look much simpler in this machine.

ok, so i tested the pressure and found that the group gauge is reading about .5 - .75 bar too low. I was pulling shots at a reading of 9.5 bar, which was actually 10-10.25.

I lowered the pressure appropriately and the first shot I got seemed perfect. Then, that was the last perfect shot I got. I went through 3 bags of coffee trying to chase that picture-perfect shot. I'm starting to wonder if I'm being too picky. I self-argue that I should be picky considering the amount of money I've spent on all this.

Anyway, I still am getting channeling. Ugly bottomless pours, and pucks that press hard against the screen when done. Pinholes in the puck. I've tried lower profile dispersion screws/screen (EP sproline) and that doesn't seem to make any difference.

When I measure the shots with the refractometer, I am getting between 18%-19% Yield. I have seen solid 20s sometimes, but am I being too picky with this? I get a "proper" shot maybe one in ten attempts. I know when it happens, and it tastes proper, complex, beautiful. Is this a "god shot" that I shouldn't kill myself over if I'm not getting it every time? What should my expectations be with this kind of equipment? So frustrating.

PS If you are in NYC and you can troubleshoot/dial-in this stuff, please PM me. I am willing to pay if you got the chops. Just want to figure out if its the equipment or me!