I am having resistance overload issues of some kind, on my direct connection 240 V hot-tub water heater. This is a 110 V /240 V heating element. The red wire gets quite hot all the way up the dpst switch. At one time, it melted the insulator at the heating element. Is this due to a bad wiring at the heating element which I need to s More seriously clean or is there more? P.S. there is zero computer control panel.