http://www.boards.ie/vbulletin/attachment.php?s=a7c3049d65d4bd0fbc96861cbfeee14c&attachmentid=95959&d=1258066668
Is a picture of the reset. With the power off, remove the case, 2 screws (use bolt adapter if no room for screw driver). Unhook case and lift off.
The reset switch is located just after the two blue marks on the image (just after the plastic casing if you can't see the image).
Simply press that away from you, towards the wall quite hard (make sure the power is off first). To test, turn the power back on and twist the input dial all the way off and then all the way on. You will see it spark.
Turn the power back off, hook the case back on at the top, align the two studs on the sides, press the bottom in and replace the two screws underneath. Voila!
It took me 2 hrs to find and do this, so I hope it works for your heater too!
Joeynix at hotmail dot com
November 2009