Wires are rated to handle a certain amount of amps. Your dryer cord is bigger than your coffee maker cord because your dryer pulls more amps. What is going on with your heater is your heater is drawing more amps than the wire can handle. Therefore the wire is getting hot, melting the insulation. Hopefully it shorts out before it catches on fire!!! BOTH BAD SCENERIOS!!! It is possible your machine is just excessively dirty, therefore working extremely hard, drawing high amps. If you are able to give a good cleaning, do so. Let dry and turn heater on DURING A TIME WHEN YOU CAN MONITOR IT, NOT OVERNIGHT. See if it has made a significant improvement. If not, it's time for a new heater!! Best Wishes!!
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