Mr Heater problem

[cinzblueyz]

I have a MHU50 heater that every time I turn on the electric it blows the three amp fuse. The thermostat is off so it is not trying to power up. I have tried many times same result. Any Ideas?

 

[klassenl]

Start by removing the thermostat wires from the board. If the fuse stays good then you know the problem is external.