A flow of 25 is far too high. If you could actually supply that much heat to it, you'd be getting 2 and a half buckets of steam a tick. The base amount is a pressure of 0, and a flow of 1, which takes 100 HU/t to give 100 mb/t of Steam. At 220 Bars and a flow of 1, it takes 200 HU/t to give 100 mb/t of Superheated Steam. Each flow increase is adding onto this again, so a flow of 3 at 0 bars will give 300 mb/t of Steam for 300 HU/t.
Now it start working, thanks a lot!