My Rancilio Z9 Two Group Lever Machine
will soon replace my Elektra T1 as my daily machine (and the Z9 will one day make way for my Model 80 LSM) - so I haven't much to offer in the way of experience with temperature management, yet. However, this thread got me thinking, looking at my Z9 more closely, and wondering about cooling flushes.
In theory (because I have little practice) it seems that I have little recourse in the way of managing the temperature coming out of the group other than through the pstat. The more I look at, the more it seems that a cooling flush would do very little to cool the group. Indeed, I think if anything it would heat the group. Whereas with my T1 I can clearly see and hear the HX heat flushing out like dragons' breath - there is no similar fire with my Z9 - it just remains a steady temperature reflective of the boiler temperature. For instance, if I open the water fill and leave the lever open, then the water cools out of the group as the incoming cold water cools the boiler.
This is a bit rambling and a bit of me thinking out loud, some of you might be saying, Well, DUH. However, it's all new to me. Below, are a couple of photos where you can see that the group is bolted directly to the frame, and (not so clearly) two tubes from each group are fed by the boiler. Oh, and FWIW, Clay's comment about 195 degrees had me measure the temperature in a cup that I kept overfilling - it was 190 degrees at 1.1 bar.