To all fellow whacked out people:

As most of you will know getting an E61 group at the right temperature is pretty important, but sometimes a bit of a hit&miss and water consuming (buggers if you're using canned water!)... On prosumer equipment at least!

What about placing an electronic controllable valve in the HX loop and using a PID controller unit to control the water flow in the loop, thereby controlling the temperature of the group? Has anyone thought about this?

Feel free to call me crazy... I'd like to fit in

Possibly like this: http://www.home-barista.com/espre...machines-t787.html
or this: http://www.home-barista.com/espre...e-fixes-t3311.html
or this: http://www.home-barista.com/espre...-pulser-t2789.html
or this: http://www.home-barista.com/tips/...-flush-t10760.html
or this:

This is not necessarily a definitive list but it would get ya going. The "auxiliary" radiator would need to be sized to simulate the heat given off by the group and you need to be able to fit the components inside the existing box - not trivial.

LOL!
I really love these boards. Thanks Eric!

Controlling the temperature of the group is relatively easy. On an HX, it's controlling the temperature of all the water that goes through the coffee that constitutes the difficult part. The steady-state condition of idling with the siphon going is, on most HX machines, quite different from the transient conditions of pulling a shot. In other words, a group at a steady temperature does not guarantee that you'll get a shot at a steady temperature.
-Ed