The VF2500 and VF2500 Plus stoker furnaces offer convenient, economical and powerful heating with rice coal. The hopper will hold enough coal to operate the furnace for as long as five days. Coal is fed from the bottom of the hopper by the VertiFlow stoker system. Feed rate is controlled by the ESP based temperature control. This assures that each piece of coal is held at high heat for sufficient time to achieve complete combustion.