Pressure of 2d ?
 

What should the water pressure of the 2d be set to ? ie how does one know when the correct pressure has been set ? Is there any down side to "too high" pressure.

The 2d pressure is factory set to approximately 6-7 bar - includes the hystersis of ther pressure. If an accumulator is used, the pressure stays more towards the 7 bar side, sometime peak to 7.5bar.

You need to measure the water pressure with a gauge with the engine running - it should be set to the above mentioned.