The main function of a chimney is to create good combustion as well as transport the gases from said combustion out of the home. A good draft is vital for good combustion. We consider that a good shot should be between 10-20 Pa. Poor installation or a defective chimney can cause smoke buildup, which will never be created by the stove itself.
The basic thing to have a good draft is to have an optimal smoke outlet built.
A tall chimney provides greater draft. If the draft is insufficient, the solution may be to simply make a higher chimney. The diameter of the pipe should never be smaller than the smoke outlet of the appliance itself. A circular pipe usually provides better draft than a square one. The use of elbows reduces the draft. If elbows are used, it is better to use two 450 elbows than one 900 elbow.
Combustion air is essential for draft
An open fire requires approximately 300m3 of air every hour, while a closed appliance requires only 30m3 per hour. A kitchen exhaust fan takes in more air than a closed chimney. So this could cause a negative draft, and the chimney could release smoke into the room. If we connect outside air to the stove this would always prevent the combustion of air from being insufficient.
Wind influence
Very tall trees or roofs as well as abrupt changes in terrain can also cause draft problems. These problems are usually solved by simply making the chimney taller. In extreme situations, smoke extractors or draft regulators can also be installed to stabilize the chimney draft.
The chimney draft is produced by the heating of the air
The higher the air temperature, the better the draft of a fireplace. Better results occur when the diameter of the pipe matches the diameter of the appliance. Too strong a draft can cause the heat to go too quickly down the chimney draft. A draft that is too strong can be regulated with an air deflector, draft regulators or restrictors. Using elbows also reduces draft.