The Helios Fans WHR 4÷50÷25 30 is a warm water heater battery designed for use in duct systems, featuring flanges on both sides for secure installation. The casing is constructed from galvanized sheet steel to ensure strength and corrosion resistance. Inside, the heat exchanger is equipped with copper pipes and aluminium fins for efficient heat transfer. The unit supports a maximum operating temperature of 120 °C and a pressure limit of 8 bar. Water connections come with external threads to facilitate easy integration into heating systems.