WDR Series Electric Heating Boiler WDR series full automatic electric heating boiler is a kind of new high technology product which takes electricity as energy. It has the advantages of environmental protection, no pollution, no noise, convenient installation, small occupation, full automatic control and high thermal efficiency. Core Technology: 1. Over pressure, over temperature, low water level, air ignition alarm interlock; 2. Power off, under voltage, over current, short circuit, phase loss shutdown; 3. Automatic control; 4. Stainless steel tube type nichrome electric heating tube; 5. Outer packing of stainless steel plate.