HIU flexRAD, with hot water priority circuit, compact hydraulic interface unit for hot water production by continuous flow principle and transfer of heat to radiator heaters. Installation as flush mounted version with flush box or as surface-mounted version with cover. The pipe connection to the hydraulic interface unit is created using a patented installation system with pre-installation bracket. Option to connect the pre-installation bracket from below.

Consisting of:

• Copper-soldered asymmetrical stainless steel plate heat exchanger;
• HERZ pressure and temperature controller for central regulation of the hot water temperature with hot water priority circuit;
• Control valve with return temperature limiter for low heating return temperature;
• Constant readiness for hot water preparation even in summer operation due to temperature-controlled bypass circuit, fixed at 45 °C;
• Warm and cold water meter adapter piece 130 mm – G 3/4", also suitable for continuous operation;
• Adapters 80 and 110 available as accessories;
• Heat meter adapter 110 mm – G 3/4", also suitable for continuous operation;
• Strainer with fine mesh in the primary supply line and secondary return line;
• Differential pressure controller (20 kPa) in the secondary circuit;
• Differential pressure controller (25–60 kPa) in the primary circuit;
• Empty weight module: 15 kg;
• Connection: MT 3/4" flat sealing;
• Max. operating pressure: 16 bar;
• Max. supply temperature: 85 °C;
• Min. drinking water flow pressure: 2.8 bar;
• Thermal readjustment;
• Circulation set: 1 4028 57;
• Flush cabinet short: 1 4028 47;
• Front frame with door short: 1 4028 48;
• Cover HIU flexRAD: 1 4028 54;
• Pre-assembly strip HIU flexRAD: 1 4028 55;
• Adapter piece for heat meter sensor M 10 × 1 mm: 1 4022 46.