Yes, the Oscar has the same problems.
It is necessary to make two gicleurs (3.0 and 3.2 mm) on drawing:

To establish from a group head in hot and cold lines. The cone form will help the gicleur to be kept in a tube 6 mm:

Hi, Rostislav.

Considering this problem, even while I don't have group temp measures, I did two tests today, measuring the hot pipe temperature. But my OPV (same place as the original neplax, after the HX) is set to 9 bar, so the flow at the HX is around 4-5 ml/s (I've run the tests with the 3-way valve closed, similar to a very tight ristretto ).

I got a declining temperature. First test was around 1 bar, second test was around 1.2 bar. In both tests I did flush until flash boiling water had stopped. I'll try with the OPV set to 12-13 bar to see what happens, then I post some data.

Have you installed the glicleur? They are original or you had to make them? Do you have new data of your TC at the group?

Márcio.

Yes, I have established gicleurs. The temperature of metal in the field of the dispersive screen has decreased till 82-83 С.
The temperature extraction was stabilized (changes no more 1С)

I didn't understand if you are using the original Simonelli parts or if you made them...

Interesting that I was thinking that the smaller gicleur (3mm) was on the inlet tube, but it's the other way, 3.2mm at the inlet and 3mm at the outlet. I think Simonelli found this balance to the idle thermosyphon flow and a little bit of higher flow to the hot inlet when pulling a shot.

But looking at the Musica parts book I see that now they have a "by-pass valve", hence an OPV, right after the pump (01000159 part) and the neplax after the HX is 16 bar, probably just a safety valve for the HX loop. So if your pressure is set around 9 bar, for sure the flow inside the HX is always around 1-2 ml/s depending on the shot.

Márcio.

Original gicleurs attract replacement of a head of group. Easier to make.
Yes, Simonelli found balance to the idle thermosyphon flow and a little bit of higher flow to the hot inlet

Hi Mitch,

I have a single group Linea (120 V) and have operated it in several configurations including as original with the Fenwal thermostat to its present evolution with PID and the Piero group cap. If you would like, I can provide solid information on this machine along with pics and Scace temp performance. PM me or I can post here although this thread has drifted a bit OT.

Cheers,
Bill near Daytona

OBTW Chris' comments are right on the money.