hi get in touch with white knight,its dangerous and should not be used.if it has started to melt the door I would also be concerned about internal damage too.don't touch it its a fire hazard.don't waste your time and put yourself at risk.with that much heat the T/stat should of cut in.phone them immediately.doesn't matter how old it is.be firm and remain calm on the phone,if white knight send an engineer don't let him take the tumble without a replacement .
m, December 2011