Hi seabee. The hopper feed system was optional on the original wood burner design. The hopper was hard to keep sealed and draft loss was a common result. Fires were therefore hard to keep going. It was redisigned as a coal burner in the Vigilant II, model 2310. isn't sold as a wood burner as it does not meet the EPA particulate spec. It comes with a restrictor plate over the inside inlet hole to reduce air intake volume when burning bituminous. The outside inlet is regulated by a bimetalic coil controled metal flap. Works great. I've had wood fires in it with the restrictor plate inplace. With out it, wood fires quickly get too hot. I also bought a screen from Vermont Casting to use the stove as a wood burning fireplace with the twin doors opened/removed.
I heat a ~3,100 sq. ft. well insulated house burning anthracite. Opperating stovetop temp range is 400 -700 F. I can heat with it unless it gets really cold when I suplement with the central oil hot air unit. I don't think I've burned 20 gallos of #2 this year since I started the caol fire in November.