How to clean the chimney and achieve good draft of the stove or fireplace

Recommendation points

• The main problems of lack of traction in the furnace
• 1. Pipe length
• 2. There is no windproof cap on the pipe
• 3. Leakage of the chimney
• 4. Insufficient tightness of internal chimneys
• 5. Insufficient tightness of the combustion door
• 6. Blower of insufficient length
• 7. Clogged air ducts in the oven
• 8. Formation of resinous (tar) deposits in the furnace and chimney
• 9. Long pause in furnace operation
• 10. No stable draft is created due to the small volume of the combustion chamber
• 11. Small or large chimney volume
• 12. Many devices are combined into one chimney
• Folk tricks and traditions of cleaning chimneys

Poor draft in the stove, smoke goes into the room and not into the chimney, soot quickly accumulates in the chimney, the flame flares up and goes out quickly – everyone who has a stove has encountered these problems. Is it possible to solve these problems on your own without resorting to the help of professionals, let’s figure it out together.

Draft is a natural and directed movement of air masses in a chimney due to convection flows, in other words – warm air expands and becomes lighter, rises up, and cold air comes in its place. The movement of gases in the chimney is also due to the pressure difference: in the furnace it is large, and outside it is less, and therefore there is a continuous expulsion of heated air out.

The main problems of lack of traction in the furnace

Stove makers identify twelve main problems of lack of traction in the operation of stoves..

1. Pipe length

Technologically, the pipe should be 50–70 cm higher than the ridge of the roof. This is enough so that the vortex air currents at the ridge of the roof do not interfere with the exhaust gases. It so happens that in a strong wind, the flow swirling from the ridge (turbulence) in terms of pressure exceeds the pressure of the exhaust smoke and, as a result, a reverse thrust occurs in the pipe.

2. There is no windproof cap on the pipe

The situation is the same as with the roof ridge: the air flow in terms of pressure exceeds the pressure of the exhaust gases and the convection flow cannot come out completely and part of the smoke goes into the room.

1 – reverse thrust; 2 – normal thrust

3. Leakage of the chimney

It happens that due to seasonal fluctuations in the soil (swelling of the soil when freezing) or other reasons, the stove shifts from its original position and the chimney moves. Due to this process, it is possible to disconnect parts of the chimney, cracks in the masonry, etc. These problems lead to depressurization of the chimney in its technological part and the pressure difference becomes insufficient for the complete removal of gases.

In addition, such a problem is fraught with fire, since the sparks discharged by the gas do not have time to cool down and, coming out in the wrong place, can cause a fire..

4. Insufficient tightness of internal chimneys

Cleanout doors, ventilation wells and convection chambers are not laid out according to requirements.

5. Insufficient tightness of the combustion door

The flame forms a powerful convection flow of hot gases and, when firing up the smoke, it is easier to get into the room than into the chimney, so it is necessary to keep the fire door closed as tightly as possible.

6. Blower of insufficient length

The blower provides the required amount of oxygen for combustion. If it is small, then the combustion process will be in short supply and the temperature for the formation of a stable convection flow in the pipe will be low. In this case, it is easier for the stream of smoke to go outside through the fire door or other places of the stove directly into the room..

7. Clogged air ducts in the oven

Chimneys inside the stove are rarely cleaned. Pay attention to each turn in the masonry, in which the direction of the air flow with the exhaust gases changes. Usually, it is at turns as a result of flow eddies that soot accumulates..

8. Formation of resinous (tar) deposits in the furnace and chimney

All slow-burning furnaces “sin” with this if they burn birch wood or wood with a high resin content. Due to insufficient combustion temperature, resinous and tar compounds do not burn out completely, but condense on the walls.

9. Long pause in furnace operation

In summer, when it is warm outside, the heating stove is idle, as a result of which moisture accumulates in the chimneys. When the furnace is kindled, it evaporates and for some time denser and viscous layers of air are formed, which interfere with the removal of gases out through the pipe (so-called air locks).

10. No stable draft is created due to the small volume of the combustion chamber

This is often the case with low power factory ovens. The length of the chimney turns out to be long so that the convection flow pushes the air cushion in the chimney. A similar situation is when a heat exchanger of the heating system of the house is built into the firebox. In this case, the volume of the furnace must be laid 25% more than usual to create a stable draft in the chimney..

11. Small or large chimney volume

In fact, the phenomenon of smoke removal through a chimney is similar to the jet movement of gases. If the chimney is narrow, then it is impossible to create a stable and directional flow inside it, therefore a gust of wind or a change in the combustion force in the firebox can lead to the formation of a back pressure zone inside the chimney channel. A similar situation with a large chimney section.

12. Many devices are combined into one chimney

It so happens that when building a barbecue, a stove with a hob, a brazier, a smokehouse and a fireplace are attached to one chimney. As a consequence, the throughput of the chimney does not withstand such a load and “clogs up”.

Folk tricks and traditions of cleaning chimneys

Sooner or later, the stove and its chimney have to be cleaned. If the air ducts inside the stove can be easily cleaned with a long scoop and a hard broom, then long pipes can be almost impossible to clean, however, over hundreds of years of operation of stoves in many parts of the world, their own cleaning tricks have appeared with minimal costs.

For example, in Siberia, chimneys and pipes are cleaned by burning freshly chopped firewood of freshly sawn aspen in a furnace. When burning wood, moisture evaporates, then it condenses on soot, which increases its weight and crumbles into places, from which it is then cleaned off. It is recommended to use this method no more than once a season..

The Pomors had this way of cleaning chimneys (do not repeat – this is cruelty to animals) – a long rope is tied to the cat and then thrown into the chimney (the stove, of course, is cold and does not heat up). The animal is forced to run down to the firebox door, where the owners are waiting for it. A broom is tied to the end of the rope that remained on the roof of the pipe, and a rope is pulled at the end that was removed from the cat. A hard broom, passing through the chimney, strips off all the soot in it.

In Belarus there is a way to clean soot in chimneys – it is to throw potato peelings on hot coals. Organic compounds of potatoes, interacting with soot, actively destroy it and, if you look at this process from the street, you can see how whitish flakes fly out of the pipe. The level of soot deposits from such a procedure is reduced by 1/3.

In Ukraine, there is a popular way to clean chimneys – to throw table salt into the fire. Indeed, after such a procedure, the amount of soot in the chimney becomes much less.

And, of course, the most effective way to clean pipes is to use a long special brush (ruff), which, having a certain rigidity, scrapes off soot deposits on the walls of the chimneys..