Blocked Chimney

• A chimney blockage is the most obvious reason why it will not draw properly. A chimney without a cap may have a bird's nest in it, which is often only discovered when the first fire of the season is started. If you have access to the top of the chimney, removing a nest may be an easy task. You can poke it from the top so that it falls into the firebox and can be removed from there. Ensure that the entire nest is removed. Bird's nests are full of bacteria; wear a protective breathing mask, and wash up afterwards.
  
  

Mechanical Failure

• A fireplace depends on a damper system to allow smoke to leave the firebox. The damper is at the firebox level, and sometimes at the top of the chimney as well. If the damper system is stuck in the closed position, it guarantees no smoke with leave the firebox. Because the damper is usually at the back of the box, it's sometimes difficult to see if it's working properly. When the firebox is completely cold (no fire burning), shine a bright light to the back of the box and see if the damper moves when you pull or push the control knob or lever. If it moves with difficulty, it may be rusted and needs cleaning. If you can remove it yourself, clean and oil it. If not, call a professional in.
  
  

Fire Building Problem

• Many chimneys don't draw properly because of a poorly built fire. Using unseasoned wood, pieces too large to start with or letting the fire smolder too long can all cause the smoke to build up faster than the chimney can draw it away. Using small kindling wood that quickly builds up a bed of hot coals, followed by adding medium, then large pieces of wood, helps to prevent overloading the system. Placing too much wood in the firebox at once can also prevent proper air circulation.
  
  

Cold and Wind

• A cold chimney will not draw smoke until it is warmed up. If the chimney is located outside the house, it may take concentrated effort in very cold weather to warm the chimney enough to create a draft -- especially if there is a strong wind. Before starting the fire, heat the air in the chimney by holding a burning newspaper or similar item up to the interior flue. It make take 10 minutes or more to warm the chimney enough so that it begins to carry the smoke upward.