Thermoflo OWT Series 3 Oil-Fired, Water Boiler with Tankless Coil, #OWT-3 thru OWT-6, 98 MBH - 196 MBH InputOWB Series 3 Thermoflo Spec Sheet Factory Packaged 0. 70 to 1. 75 GPH # 2 Fuel Oil Efficiencies 85% 87% AFUE Enhanced control Temperature limit control LWCO Function Thermal pre purge function Rear flue outlet Top flue available with optional kit Easy service Swing away burner door Top access cleanout cover Plug in wiring harness High efficiency oil burner Solenoid valve PSC motor Solid state ignitor Cast iron sections with built in air separator