1. Because the electric heater itself has been damaged, the surface will become black. If so, the product does not need to be used again and replacing a new heating element is recommended.
2.Due to the abnormal power supply system or cutting off the power supply. In the application of electric heating element power failure or abnormal power supply system harm all normal application, will appear black situation.
3. The point contact of the control panel is loose, and the power cable plug and electric heater power socket are loose.
4. The oxidation of electric heater to air, after application ,the electric heater, due to the harm of gas or wet and cold natural environment, the surface form several gray black blocks due to the oxidation of air , with a flame like burning stainless steel plate, the surface becomes gray black chemicals. It is more common, and this kind of gray black metal oxide is non-toxic, electric heater element can be applied again.
Therefore, when the electric heating element is heated for a period of time, the surface will become bad, people should identify why it is caused. If it also has resistance and still works, it means it's just air oxidation; If there's no resistance it mean burned.
