Roman,
The last time I had the E3.1 and E3.4 coming up it was due to a faulty Pressure Sensor Block on the Multiplexer. You can use the Service Mode n38 to check the water and air pressures (according to the unit) then stick a manometer on to the syringe for comparison.
If the foot switch ploblem is on another planmeca chair it may need calibrating, or I have had the screws holding the top PCB coming loose before so that the sensors move.
Planmeca parts in the UK from Plan Dent 01707 822420 for Rob in the speres Dept.
Lee
