Very likely the heating element - a resistance wire that gets hot and expands naturally - if the electric wire touches the outer case of the element then current leaks to earth.
The ELCB compares the current in the live and neutral wires and if different it assumes the missing current can only be going to Earth and possibly through a person - it's a safety thing - and it trips out to prevent electrocution.
Of course it might not be the heating element but I'd say it's at least 90% certain that it is - I'm just guessing.
Your realistic options are to try to repair it yourself or to have somebody call and do it for you - I suspect that there may be videos on youTube that show how it's done - the element will be very low down in the machine due to the way water behaves.
Good Luck..., June 2016
