Hi, I've got one of these, my heater has packed up today.
I did look at the unit to try and fix it. There are two heating elements one gets a feed when unit is turned on, the switch on the front puts power onto the second element. So when set to hi both elements are on, so I expect the first element is blown and you are just running on the second element. To prove this I would have thought that you would notice that the temp is low!!! Only a guess from what I've seen... It looks like you need to replace the element (both in the one unit). Unsure on how complicated this is!!
Hope this helps
aandy, January 2006