I found this with my green compact drier however, the reset button had a red plastic shroud which prevented it from being pushed in to reinitiate a reset, by really pushing it so that it "clicked" I had heat return.
My WK also isn't the rear tubed type and by vacuuming out all the side and front vents, the machine was like new...
Ian Watson
Unity Injustice
Ian Watson, October 2005