Kenjo
Yes, you are right it is a double element but its more complicated than 3 wires. There are the following wires. From the reset button - 2 blue wires. From the thermostat - 2 black wires. From the machine - 2 black/white wires, 1 earth, 1 red, 1 black, 1 blue. Really appreciate your help.
Russell, October 2013