HELIOTHERME 4000® Axial air heaters Three-phase HELIOTHERME control (AC motor)® 3-PH Eco+ BOX range Figure C 3-PH 400 V + T + N Multiple unctionj /50 Hz box RS485 connection Slave unit: 3-PH 400 V + T + N /50 Hz supply Master controller: Self-powered by a four-wire (12 V) RS485 bus Figure D Slave unit: Master controller: 3-PH 400 V + T + N /50 Hz supplySelf-powered by a four-wire (12 V) RS485 bus All-electric HELIOTHERME control® (diagram in Eco+ ELEC BOX user manual) Eco+ ELEC BOX range Figure E Slave unit Master controller CATALOGUE 2021 193 193