My pellet stove has big flames: causes and tips to solve the problem

My pellet stove makes big flames ", " too many flames in my stove ", " why does my stove produce huge flames? "...many users complain about abnormally large flames from their pellet stoves or pellet stoves. These oversized flames are not only detrimental to the efficiency of the heating system, but also dangerous. 

In this article, we explain why your pellet stove produces too big flames, and then offer you tips to solve the problem. 

Pellet stove : how to recognize a normal flame

Color, size and shape of the flame 

The pellet stove is a heating device that uses compressed wood pellets as an energy source to produce flames. The question we are interested in here is: what are the characteristics of the ideal flame ? It's simple: we're going to talk about the color, size and shape of the flame. Let's explore this in a little more detail. 

Let's start with the color of the flame. Under normal conditions, it should be blue to bluish-yellow, indicating complete and efficient combustion of the wood pellets. A flame of this color indicates that combustion is occurring at an optimal temperature, which ensures high energy efficiency and reduced emissions. 

The size and shape of the ideal flame depends on the settings of your pellet stoveIt also depends on the model you have. Generally, the flame should be moderate in size, stable and well distributed in the combustion chamber. 

The quality of the combustion

The combustion quality in a pellet stove can be influenced by several factors, starting with the quality of the pellets, the air supply and the stove setting. Good quality pellets have a low moisture content, a high density of raw materials (especially wood chips and sawdust), a uniform size and a regular cylindrical shape. They must also be free of contaminants and harmful additives. Failure to do so will result in incomplete combustion and you will likely see excessive soot deposits. 

Optimal combustion also requires a good adjusting the airflow of your pellet stove. The air supply can be impacted by burner fouling, which in turn will lead to overly large flames. If the lack of oxygen impacts the quality of combustion, the excess air tends to cool the flame, reducing the efficiency of the stove.

Finally, keep in mind that incorrect or inappropriate settings of your pellet stove (auger speed, heating power, air supply ...) can affect the quality of combustion and produce large flames. Hence the importance of adjusting your pellet stove according to the size of the room to be heated, referring to the technical data of your pellet stove and the advice of your installer.

Good maintenance of the pellet stove = optimal flame 

My pellet stove does not heat enough ", " my pellet stove heats too much "...often these problems are the result of a lack of maintenance of the furnace. 

You are probably not learning anything by telling you that regular maintenance of your pellet stove is essential to ensure its proper functioning, prolong its life and ensure your safety. It is also what keeps the flame normal, ensuring optimal energy efficiency. But how to maintain a pellet stove in the rules of the art? The answer in a few key points: 

  • Cleaning the burner and combustion chamber, regularly removing ashes and combustion residues to prevent soot build-up and maintain a good quality flame; 
  • Checking and cleaning of the flue pipe (which must be well dimensioned) for a good expulsion of smoke and combustion gases;
  • Inspect and replace gaskets, especially those around the door and vent, for signs of wear or damage;
  • Regular checking and cleaning of the auger and pellet tank to prevent blockages and ensure a constant supply of pellets. 

In addition to regular maintenance, ideally performed on a weekly basis, it is essential to perform a more thorough annual maintenance of the device. This has been mandatory in EU countries since 2009. In France, for example, the annual maintenance of the pellet stove must be carried out by an RGE certified professional, for obvious safety reasons. This maintenance is highly recommended in autumn, to ensure the optimal functioning of the equipment in winter. 

Poor maintenance of the pellet stove: what consequences?

As you can see, poor maintenance of your pellet stove can lead to a decrease in heating efficiency, an increase in pollutant emissions, the production of large flames, and even fire risks! 

Neglecting the maintenance of your pellet stove will cause the burner and the combustion chamber to clog. Indeed, the lack of maintenance will encourage the accumulation of ashes, combustion residues and soot (the pellet stove fills with black soot), which causes air openings to become clogged and oxygen supply to be reduced, reducing the efficiency of the unit. In addition, excessive clogging often leads to overheating of the stove components, accelerating wear and tear on the parts that make up the stove and increasing the risk of fire. 

In addition, inadequate flue cleaning can lead to the accumulation of creosote, a highly flammable by-product of wood pellet combustion. Creosote tends to clog the flue, reducing the stove's ability to properly vent flue gases and smoke. Result the fumes are forced back into the room, posing a risk of carbon monoxide poisoning. 

Large flames in the pellet stove: what solutions?

The flame of your pellet stove is too big? Don't panic, you have several options. Here's an overview. 

Pellet quality 

As we told you, the quality of the pellets plays a key role in the performance of the combustion and the production of great flames. But how to choose quality pellets ? First of all, make sure that the pellets comply with international quality standards, such as the ENplus standard or the DINplus standard, the reference in this field. These standards guarantee that the pellets have a low moisture content, high density and energy content, good mechanical strength and density, the origin of the wood... 

In the EU, the criteria for choosing "A1" pellets for domestic heating are governed by the EN 15 961-2 standard (corresponding to the international standard EN ISO 17 225-2). For a pellet to comply with this standard, it requires, among other things: 

  • A diameter between 6 mm ± 1 or 8 mm ± 1 ;
  • A length between 3.15 mm and 40 mm;
  • Moisture content less than 10 % to ensure complete and efficient combustion;
  • An ash content of no more than 0.7 % (higher ash content may result in excessive burner and combustion chamber fouling) ;
  • A minimum mechanical strength of 97.5 %, etc.

Where to store the pellets ?

Pellets fear humidity, which affects the quality of combustion, causing the production of large flames. Hence the importance of storing them in a dry and well-ventilated place. 

Often, individuals prefer to store their wood pellets outside, as long as the space available allows it. Ideally, make sure to store your pellet bags in a garden shed or garage. In case the pellets are packaged in bulk, make sure they are stored in a place that is easily accessible to delivery people.

In case you can't store your pellets outside, it is possible to keep them at home, while protecting them from humidity. Where can you store them? Laundry room, back kitchen, cellar... you have a lot of choices. The main thing is to keep them in their original packaging, protected from water, and make sure that the place you choose is well ventilated. Finally, you should know that there are boxes specially designed to store pellets in a dry place.

Adjusting the flame of the pellet stove 

As we said, the size of the flames of your pellet stove is influenced, among other things, by the settings of the device, including the air flow through the fan. It is important to know that the burning speed of pellets depends on the amount of air. 

To solve the problem of large flames and optimize combustion, be sure to adjust the settings of your pellet stove. In addition to the airflow, you should adjust the speed of the auger by referring to the user's manual for the manufacturer's recommended settings. This will allow the stove to be fed with the right amount of pellets, thus avoiding over-feeding and the production of large flames. If in doubt, do not hesitate to call a qualified professional.

Can a pellet stove run continuously?

Yes, a pellet stove can run continuously. However, it will be necessary to turn it off from time to time, for example to clean it, or to avoid the risk of burns when you refill it with pellets. 

My pellet stove makes big flames : conclusion

Unusually large flames in a pellet stove can be related to a variety of factors such as pellet quality, stove settings and maintenance. To remedy this problem, it is important to choose quality pellets, store the pellets properly, adjust your stove settings and perform regular maintenance. 

By following these tips, you will not only ensure optimal energy efficiency, but also safe operation of your pellet stove without the risk of fire. 

Do not hesitate to consult a professional in case of doubt or for a thorough annual maintenance. In this way, you will be able to fully enjoy the heat and comfort of your pellet stove while preserving the environment and your safety.