Abstract: A heater for burning particulate combustible fuel material, and a stoker for transferring the fuel for use in connection with such a heater. The heater includes a burner with a step upward from the stoker onto the burner, for reducing the possibility of the fire burning back into the supply of fuel. The stoker includes a first conveyor and a second conveyor, spaced vertically apart and connected together by a drop box. A drive arrangement for driving the conveyors includes a prime mover connected to the first conveyor by means of a drive shaft and to the second conveyor by an intermittent drive. The intermittent drive includes a second shaft with a plurality of paddles extending radially outwardly therefrom. In one embodiment, one or more paddles are removably affixed to the first shaft and extend radially outward therefrom. Thus rotation of the first shaft causes rotation of the second shaft only when the paddles are in contact.