Weil Mclain WGO Packaged Water, Oil Boilers, less burner, without Tankless Heater Opening. Burners are sold separately. Weil Mclain WTGO Packaged Water, Oil Boilers, less burner, with Tankless Heater Opening. **Please note The WGO & WTGO boilers come without a burner. The burner is listed in the product information and must be ordered separately.