Protect your boiler or heater from freezing with this compact freeze‑protection valve set. Weighing just 240 g and rated up to 2.8 bar, it fits C 3402/4002/6002, Combi 4/6 (E) from June 2007, Combi D 6 (E) from May 2008, and E‑Boiler models since 2004.