Heating element is the essential component of electric water heater. It is made of metal sheath, insulating magnesium powder and heating wire. Metal sheath are mainly copper plated steel, stainless steel(SUS304, SUS316, SUS321), and incoloy(incoloy800 and incoloy840). Currently stainless steel and incoloy are widely used. The quality of electric heating element is directly related to the safety of using water heater. Therefore, you should pay more attention to the electrical performance of heating element besides watt & volt of it when buying a water heater.
It is very complicated to produce heating element with over 30 procedures to go, such as powering and pipe-shrinking. For now, Standard JB4088-98 and Standard GB4706.1 are mainly adopted in manufacturing heating elements, which asks for a minimum of 3000 hours lifespan in normal use. Some heaters also choose imported incoloy800 as material. Because incoloy800 has anti-scale surface coating making it better at anticorrosion and keeping parameter of electrical performance unchanged even after hours heating in air.
To better meet customers’ needs, water heaters are developing with multiple heating elements. Most water heaters in the market currently are installed with two heating elements, some even with three. Mainly it is to meet customers’ need of using different watts with different water volumes in different seasons to heat faster and more efficiently. It is to say you can turn one heating element on or all 3 at the same time.