Why Does Smoke Puff Back Out The Door When Loading Wood?
You may have insufficient draft. Debris or creosote could be blocking the flue. Inadequate chimney height or design could be causing downdrafts. Check chimney connector for air leaks and seal with furnace cement. Adjust barometric regulator to higher setting. Your home could be so well insulated that infiltration air is not getting in to replace air used in combustion. Open a window slightly in furnace room or install a vent to the outside in furnace area.