The RS 310-410-510-610/E-/EV-/EVi Blu burners series covers a firing range from 1200 to 6250 kW, and it has been designed for use in low or medium temperature hot water boilers, hot air or steam boilers, diathermic oil boilers. It is based on the Digital Burner Management System, Riello REC27-37, which is able to manage the air-fuel ratio by independent servomotors in order to obtain a perfect output control and to assure a correct combustion and safe operation on all modulation range. Operation can be “two stage progressive” or, alternatively, "modulating” with the installation of a PID logic regulator and respective probes. RS/E-/EV-/EVi BLU burners series guarantees high efficiency levels in all the various applications, thus reducing fuel consumption and running costs; specifics versions are available to operate with Variable Speed Drive technology base on the control of a Frequency Inverter that modifies the air flow through the motor speed variation. The RS/EVi models provide a Variable Speed Drive System integrated with the fan motor for a compact solution and an easy commissioning. The combustion head engineered with advanced simulation devices, guarantees reduced polluting emissions (NOx < 60 mg/kWh) The exclusive design ensures reduced dimensions, simple use and maintenance. A wide range of accessories guarantees elevated working flexibility.