Maintenance has been described in the user manuals. In addition, this tutorial contains movies that show the procedure in more detail. Before using this material read the instructions and warnings in the user manual.
Initialization of an electric Valco valve is a 2 step procedure. First the head is removed and the valve must be switched 2 or 3 times (you hear slowly switching). Secondly, the valve is mounted and firmly fixed. Then the valve is switched until the switching speed is really fast. The initialisation procedure is also described in the manual.