... 1.Electrical boiler has a small size, high efficiency; 2.energy-saving, no noise,easy to be installed; 3.a new ... open the cold, hot water valve,the system will switch to hot water automaticaly, which is operated simply;D: ... high-pressure protectionG: Proof-wind protection,Overvoltage water heating system security protection, flameout protection, temperature sensor failure protection, temperature ...