Guide · Pellet stove
Pellet stove smoking: causes and what to do
If smoke is coming into the room, switch the stove off at the panel without unplugging it, open the windows and leave the room: there may be carbon monoxide. Dense white smoke on lighting almost always comes from a dirty burn pot, damp pellets or too many pellets. Black smoke from the chimney means combustion with too little air. In both cases the stove needs cleaning and, if that is not enough, a technician's check.
15 minutes Difficulty: MediumUpdated 25 October 2026
Smoke in the room with the stove on is an emergency: the fumes contain carbon monoxide, a gas you cannot see or smell. Switch off at the panel without unplugging, so the fan keeps carrying the fumes out. Do not open the door, throw the windows open and leave the room. With a headache, nausea, dizziness or drowsiness, leave the house and call 112. Do not light the stove again before it has been checked.
What you need
- Ash vacuum
- Torch
- Carbon monoxide detector
Step by step
Tap a step to mark it as done.
White smoke on lighting: when it is normal
In the first minutes the igniter heats the pellets, and a wisp of pale smoke before the flame is normal. The first lighting of a new stove also gives off smoke and a smell as the paint cures. Manufacturers ask you to ventilate the room well.
Dense white smoke that fills the chamber is different. The Cadel manual links it to three causes: too many pellets in the burn pot, damp pellets or a dirty burn pot. That smoke is harmful, and the gases that do not burn can ignite all at once with a violent puff in the chamber. That is why pellets must never be loaded into the burn pot by hand and the burn pot must be emptied after every failed lighting.
If the burn pot is clean, the pellets are good and the white smoke keeps coming back, suspicion moves to an igniter that heats too little or to poor draught. That calls for the technician.
Black smoke from the flue
Black smoke is soot: the pellets are burning with too little air. The Cadel manual lists among the causes an encrusted burn pot, recognisable by a weak red flame, then combustion air not arriving, a blocked flue or a stove clogged inside.
With black smoke the glass usually blackens within a few hours as well, and there is more ash. Clean the burn pot and its housing, check that the air intake behind or under the stove is clear and that the pellets are good quality. If it continues, the problem is in the flue or in the combustion setting, which is the technician's job.
It should not be ignored. Soot settles in the flue and narrows the passage, and manufacturers remind you that large deposits can catch fire.
Smoke in the room or from the door
In a pellet stove the smoke fan pushes the fumes into the flue pipe. If the pipe and joints are not airtight, smoke comes out into the room. The most common causes are worn door gaskets, flue pipe connections that do not hold, a blocked flue and a faulty smoke fan. The Cadel manual warns that running the stove without the smoke fan is harmful to health.
Wind against the chimney can push the fumes back and trip the pressure switch. If it happens often, the position of the chimney needs reviewing. During a power cut the fan stops: keep the door closed and ventilate. When power returns, many stoves run a cooling cycle by themselves before restarting.
There is also a less well-known case. With poor quality pellets, the Cadel manual explains, small embers can form in the pellet drop tube and travel back up to the hopper, producing dense smoke in the room. That is why the hopper lid must always be kept closed.
When to stop and call a technician
- Someone in the house has a headache, nausea or drowsiness with the stove on: leave and call 112
- Smoke in the room happens again even after cleaning the burn pot and the connection
- Smoke or ash comes out of the pipe joints behind the stove
- Black smoke from the chimney continues with a clean burn pot and good pellets
- The smoke fan is noisy or stopped, or the stove goes into a draught alarm
Frequently asked questions
Is a little smoke normal when a pellet stove lights?
A wisp of pale smoke before the flame is. Dense white smoke that fills the chamber is not: it usually involves a dirty burn pot, damp pellets or too many pellets, and the burn pot should be emptied before trying again.
Is black smoke from a pellet stove dangerous?
It means combustion with too little air, which dirties the glass and the flue. On its own it is not an emergency, but it should be fixed soon: soot built up in the flue reduces draught.
Why does smoke come out of the stove door?
Almost always because of worn gaskets, a door that does not close properly or a flue that draws poorly. Gaskets are replaced by the technician, with original spares.
Smoke comes out when it is windy: what can I do?
Wind against the chimney can push the fumes back. If it happens often, the chimney is probably in a backflow zone, too close to the ridge or an obstacle, and it should be checked.
Who checks a smoking stove in Campania?
We work in Naples and the rest of Campania: we clean the stove and the flue and check the gaskets, fan and draught. With smoke in the house, though, first get people to safety.
Read also
Ready when you need us.
Book your visit by choosing a day and time. For emergencies we answer 24 hours a day, across Campania.