Have your furnace’s chimney professionally cleaned. A buildup of soot and ash in your chimney can reduce the updraft your fire receives. If your furnace expels smoke through an exhaust system, make sure this is clean and free of debris.
Clean out your furnace's ash pan before you light it.
Burn clean, shelled corn with a moisture level lower than 15 percent only. Fill your furnace’s hopper with fuel according to the manufacturer’s instructions.
Ignite your burner using solid starter blocks. Make sure your furnace's control panel is set to give off as much heat as it can. Consult your burner's user guide for instructions on how to do this.
Ensure that your burner's door closes properly and that your system is free from leaks. If you identify a leak, contact your furnace's manufacturer if it's still under warranty, or repair any holes using furnace cement.
Refill your burner's hopper frequently to ensure it doesn't burn out.