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Stove smoke when burning wood

It’s that time of the year when the temperature starts to drop and naturally you want to light your stove. But what happens if upon lighting, your stove leaks smoke back into the room? Before you panic, there are a few reasons why this could be happening. Read on and you’ll discover that the solution might be simpler than you think…

COLD AIR

The first thing you should consider is the inside temperature of the stove. If it is too cold, the cool air will funnel down the chimney and into the stove chamber where it will remain trapped by the door and spill out through the airflow channels. Cold air is much heavier than warm air; the molecules are packed closer together and as a result push warmer air down if it comes into contact. To prevent this from happening, open the door on your wood stove and allow the interior to heat up for at least 30 minutes before you attempt to start a fire in it. Opening the doors will not only pre-heat the appliance but also jump-start the draft and get it moving upwards. At this point, you'll still want to check the draft. Light a match and see which way the flame moves. If it moves upward, the draft is good and moving, as it should. If it moves downward you'll need to find a way to reverse the draft. The only way to do this is by introducing heat. You can use a couple of fire starters to do this. If your stove has a twin-wall flue that runs up an external wall, it’s more likely that cold air pockets will accumulate due to its exposure to the outdoor elements.

UN-SEASONED FIREWOOD

Wet or unseasoned firewood could cause your wood stove to produce smoke when you light a fire. Not only will wet wood create smoke and harmful particulates when burned, the water vapour present in the warm air will make it even less dense, and will not cut through the cold air. In order for firewood to burn safely and efficiently, you'll need to make sure that it is dried and properly seasoned. This means that it should have moisture content of 20% or less. You can measure the moisture content of your firewood with a moisture meter.

TIME YOUR REFUELLING

A common mistake when refuelling stoves is to do it at the wrong time. People see the flames dying down and decide to add more fuel too soon. Fuel should only be added when flames are not present, onto hot embers. At this stage of the burn cycle no smoke is present and so cannot escape into the room. When you’re finished using the stove and the fire is out, don’t be tempted to shut down the air controls – leaving the levers fully open will allow air to flow into the stove and through the flue to help prevent the cold air blockage occurring.

POOR FLUE PERFORMANCE

Smoke escaping the appliance could be a symptom of poor flue performance. Ask the installer to perform a flue draw test to establish whether the pressure is correct in the flue system and meets the appliance requirements. It could be as simple as the baffle plate being installed incorrectly, or it may have become warped through use.