Hi,
I just bought 9 Totaline P286-1500 thermostats and even using the wiring table in the instruction manual I can't seem to understand how I can install them to a base convection Heater.
The thermostats I am using now channel a current of 240V and are installed the same way an interrupter switch is installed (lighting).
The P286-1500 have 12 inputs, where do I connect the wires?

Please help!

You have the wrong thermostats. The new ones you have are for 24 volts I believe and will not work on a 240 volt circuit.