BT N Type Single-stage heavy oil burners kW Ratings 89-189 kW Control Type Single stage (on/off) Control Mechanism Low NOx Emissions Other Mechanical pulverization Comments BT SPN Type Two-stage fuel oil burners kW Ratings 89-390 kW Control Type Two stage (high/low) Control Mechanism Servo motor Low NOx Emissions Other Mechanical pulverization Comments BT DSN 4T Type Two-stage heavy oil burners kW Ratings 223-3907 kW Control Type Two stage (high/low) Control Mechanism Servo motor Low NOx Emissions Other Mechanical pulverization Comments BT DSNM-D Type Two-stage dense fuel oil burners (High Viscosity) kW Ratings 446-3907 kW Control Type Two stage (high/low) Control Mechanism Servo motor Low NOx Emissions Other Mechanical pulverization Comments