Pellet Grills Hopper Fire and Smoke: How to Fix?

A typical pellet grill has a hopper that holds the pellets. It is possible to have too many pellets in the hopper, causing them to block airflow and cause an overheating issue. If you notice that too much smoke or flames are coming out of the hopper of your pellet grill, this blog post is for you.

So, what can be the reason for the pellet grill hopper fire or a cloud of smoke coming out of the hopper? Smoke and fire usually do not originate in the pellet grill’s hopper. However, it can backburn i.e. fire can spread from the firepot of the pellet grill to the hopper through wood pellets if the auger and hopper are jammed due to damp wood pellets or sawdust. Improper airflow due to ash buildup, and malfunctioning fan can also lead to fire and smoke in the hopper. Moreover, if you leave wood pellets in the pellet grill after cooking at a high temperature (more than 400 Fahrenheit), they keep on smoldering which can also cause fire and smoke coming out of the pellet grill’s hopper.

Two Main Conditions of Smoke and Fire Coming Out of Pellet Grill

There are two conditions during which you can observe the excessive smoke or flames flashing out of the hopper of your pellet grill. The first condition is during the operation of the pellet grill, and the second condition is when you turn the pellet grill to shutdown setting after cooking it at a high temperature and letting it cool down.

Smoke and Fire from Hopper after Shutting Down Pellet Grill

When you’re searing steaks at high temperatures i.e. above 400 Fahrenheit on a pellet grill, the wood pellets heat up to a significant extent. We usually leave the pellets in the hopper of pellet grills, keep the lid closed and let it cool down overnight. This is a drastic situation because the wood pellets in the auger keep on smoldering. Although the induction fan stops, if there is windy weather, air would flow through vents or smokestack, which will cause wood pellets to burn, due to which fire will be observed coming out of the hopper.

Also, wood pellets keep on smoldering when they get wet or you are using bad quality wood pellet brands, such as Pit Boss pellets. Moreover, if there is cold outside, the combustion gases inside the pellet grill start condensing due to the presence of water vapors. This also makes wood pellets wet and lets them smolder due to trapped heat even if you shut down your pellet grill.

At that stage, if you open the hopper lid to check, the smoke may become denser and thicker as the ambient air will boost up the smoldering process of wood pellets. This can even cause the fire to come out of the pellet grill’s hopper.

Smoke and Fire from Hopper during Pellet Grill Operation

If you are seeing fire and smoke coming out of the pellet’s grill operation, the chances are that your pellet grill is not clean. That means, there is a ton of ash and sawdust clogging the air channel of firepot holes. This will cause inefficient combustion due to which a ton of dense smoke is produced, which is being forced to billow out of the hopper.

Wood pellets are also overfed due to the blocking of the holes of the firepot of the pellet grill. This overfeeding can also be the cause of pellet grill hopper fire. Also, the ash blocks the airflow which forces the smoke to travel through the auger and escape through the hopper of a pellet grill.

Furthermore, if the air vents or chimney of your pellet grill is blocked due to carbon soot buildup, the smoke will try to find the least resistant path to exit the pellet grill. In such cases, the hopper of the pellet grill will provide the path for the smoke to exit out of the grill.

Moreover, if you use wood pellets that you left last time in your pellet grill, chances are that these wood pellets have formed a cake by absorbing moisture. If there is a buildup of damp wood pellets in the firepot, the auger could not be able to drop down the pellets into the firepot. This will cause the auger tube to catch the fire, which will try to burn back into the hopper.

Other Possible Causes of Fire or Smoke Out of Pellet Grill’s Hopper

Here are some other possible causes of smoking or fire coming out of the hopper of a pellet grill.

  • Controller malfunctioning
  • Grease flare-ups
  • Induction fan not working
  • Tunneling in hopper
  • Bad quality wood pellets

Controller Malfunctioning

Pit Boss pellet grills are assumed to have bad controllers that do not function properly. PID controllers are responsible to control the auger feed and fan speed so that a suitable quantity of wood pellets is burnt. If the controller is malfunctioning, it would try to overfeed the firepot with wood pellets, which would cause backburn, due to which fire would reach through the auger tube to the hopper of a pellet grill.

Moreover, if there is an issue in the temperature probe of your pellet grill, the controller will assume that the pellet grill needs more pellets to reach the desired temperature. This can also cause a fire in the hopper of the pellet grill.

Grease Flare-ups

If you’re cooking at a high temperature in a pellet grill, the grease in the pellet grill will ignite and will be back-fed to the hopper.

Induction Fan Not Working Properly

There are chances that the induction fan is not spinning properly, due to which it is causing excessive smoke coming out of the pellet grill’s hopper. The induction fan is responsible to control combustion by regulating the airflow. If a fan in a pellet grill seizes to work properly, thick smoke can be produced.

Tunneling in Hopper

Voids or vortex can be observed in a hopper during the operation of a pellet grill that can result in a fire in the hopper of pellet grills. Tunneling in the hopper of pellet grills is normal due to the working principle of the auger tube. In tunneling, the wood pellets stick to the side of the hopper, leaving a gap in the center. Due to the gap or void in the hopper, it provides the path to smoke and fire to burn back fairly easily.

Bad Quality Wood Pellets

Bad quality wood pellets brands are supposed to produce a lot of sawdust and ash when they are burnt. The dust is highly flammable and can easily set the fire. Moreover, it can also jam up the auger and block the airflow, due to which excessive smoke is produced out of the hopper. It is recommended to use quality pellets like Lumberjack, Cookin, and Weber GrillMaster.

Fixing Smoke and Fire Coming out of Pellet Grill Hopper

Here are the steps to fix smoke and fire coming out of the pellet grill hopper.

  1. If you’re cooking at high temperatures (above 35 Fahrenheit) in a pellet grill, don’t turn the pellet grill directly to the shutdown mode. This is because as soon as the pellet grill is set to shutdown mode, the pellets remain unburnt in the auger tube and start smoldering due to high heat transferred by the pellets in the hopper. So, before shutdown setting, set your pellet grill at low temperature i.e. 200 to 225 Fahrenheit. This will cool down the temperature of pellets in the firepot and remove them from the auger tube. When the pellet grill temperature becomes lower, you can then set it to a shutdown setting.
  2. The ground is properly leveled on which you’re placing your pellet grill.
  3. Make sure to strain wood pellets through sift pan to filter extra sawdust.
  4. Always use high-quality wood pellets brands, such as Lumberjack or Cookin.
  5. Always use fresh wood pellets. Never use the pellets you left in your pellet grill in the last cook.
  6. Make sure that the firepot and auger tube is clean. Use a shop vac to remove sawdust, ash, and charred wood pellets from the holes of the firepot and the hidden areas of the auger tube.
  7. If your pellet grill has vents, they should be opened, and there is no carbon soot buildup that is blocking the air. If your pellet grill has smokestack, make sure the cap is raised to a certain height and the smokestack is clean. Check my guide on pellet grills smokestack cap adjustment to learn more.
  8. Stir the wood pellets in your pellet grill hopper after every 30 minutes to avoid tunneling. There is a hopper grate in the pellet grills hopper. You can easily unscrew it. I would advise you to keep it removed so that you can easily mix wood pellets in the hopper. Check this forum to learn more.
  9. Avoid grease buildup in the dripping tray. Clean it after every cook. You can also add some water to dripping tray to avoid flare-ups at high temperatures.
  10. Check if the induction fan is spinning at a suitable speed and in the right direction. When the grill is turned off, manually spin the induction fan to loosen up any grime or buildup that could cause it from spinning efficiently. To verify fan spinning direction, remove grill grates and place your hand above the firepot. If you don’t feel air blowing on your hand, it means the fan spinning direction is opposite.
  11. The last step would be to replace the controller of your pellet grill. If you have a Pit Boss pellet grill, the chances are that you would have issues with the controller and auger drive. In such cases, you have to contact your pellet grill customer support.

What To Do When Fire or Smoke Starts Coming Out of Hopper?

The first thing you need to do is to unplug your pellet grill. Even the main switch is off, unplugging the pellet grill will protect the power cord. Keep the hopper and pellet grill lid as exposure to the air speeds up the combustion process.

When the smoke from the hopper starts diminishing, open the lid and scoop the pellets out of the hopper box with a nonflammable utensil. Make sure to wear heat-resistant gloves while you are doing this.