First things first, if you think 240 volt is reaching the main control board and there is nothing wrong with it, then you should have a green light lit on the control switch. If not then the main control board is faulty or 240v is not reaching the board
If it has a green light, then by setting temperature dial to 9 and then turning amperage switch through 500 1000 2000, you should hear clicking coming from relays switching elements on and off, if not then again main control board is faulty.
One other possible here is if you have a remote room thermostat plugged into the control board, if the plug has worked it's way out a bit, then this can confuse the control and it will not switch the elements on so no clicking.
Check by pulling remote out completely
If though you hear clicking then it is still quite likely the control board is faulty, burnt out relay contacts, but the limit stats Dave mentions can also be the problem,