... up to setE: Operate conveniently, liquid digital display screen with keys visible. Press the four keys, making timing, ... , fan and showerF: Anti-freeze protection, Pump-card function of stagnation,Pump bypass protection, Proof-high-pressure protectionG: Proof ... major accesories of gas boiler:Germany Weile circulating pump with exhaust valve:Intelligent proportional valve:Europ style stainless ...