10 Possible Reasons Your Stove is Burning Dirty

Do any of these phrases sound familiar with your pellet stove?
My Stove is Burning Dirty.
My Stove is Sooting.
My Exhaust is Smoking Heavily.

If so, check out this article on troubleshooting these issues.

Let's get started!

  1. Bad pellets, wet or old pellets, or pellets which have been wet at some time will not burn as clean or as hot as they should.  Try using a different bag of pellets, especially if the ones being used are old, from a torn bag, or may have been stored in a damp environment. It is important to have dry storage for pellet fuel! (P.S.-Check out our wood caddy if you're looking for a storage solution. Works with cord wood as well as pellets!)

  2. Improper installation, lack of outside air source, or using too long a pipe to bring in outside combustion air will cause air deficiency. Too long a flue pipe or too many elbows (for intake air or exhaust) can also lead to a dirty burn.  Air flow is very important to get proper performance - improper installation can cause resistance to the flow of air, causing fuel to burn dirty. Refer to your owner's manual (for the stove and for your vent pipe) for proper installation information. Click Here for Diagrams and Instructions for proper installation

  3. Leaky gaskets: Leaky door, window, and ash pan gaskets, as well as the gasket behind the burn box, will decrease available air through the fire. To test for leaking door, window or ash pan gaskets, turn the stove on without building a fire, close the door and take a lit match or lighter and move the flame around the edge of the window, around the door, and around the ash pan. If the gasket is leaking, the flame will be pulled toward the leak, as air is sucked in past the gasket. That gasket should then be replaced. Click Here to find Gasket Maintenance on the YouTube Playlist for your stove.

  4. Overfeeding: If too much fuel is cycled into the burn chamber, there is insufficient air volume to give a complete, clean burn. A bag of pellets should normally last from 16 to 24 hours (smaller pellets tend to feed faster than longer ones). If the 40 lb. bag is not lasting that long, contact customer service to have a technician walk you through a check of the programming of the control board. Call (800) 245-6489 or drop us an email.

  5. Insufficient combustion air, from a combustion blower that is not running at sufficient speed. The exhaust blower should run at about 3000 rpm. Lubrication may help a sticky motor, but replacement of the exhaust blower is the recommended course of action, since this is the 'heart' of the unit.

  6. Ash buildup in the flue: If the flue is not cleaned regularly, ash buildup will restrict air volume being exhausted from the stove. The flue system should be cleaned on a regular basis. We recommend it be cleaned at least once a month, or once per ton of pellets used. Click Here to find cleaning instructions on the YouTube Playlist for your stove.. Be sure to follow the pipe manufacturer's instructions, as well.

  7. Ash buildup in the heat exchanger/firebox area: If the firebox and heat exchanger are not cleaned regularly, ash buildup will restrict airflow through the fire. The firebox must be cleaned on a regular basis, and the holes in the burn pot must be kept clear. The heat exchanger is accessed behind the baffle, and through the two access plates on either side of the burn pot cradle. These areas should be cleaned at least bi-weekly. Click Here to find Maintenance Instructions on the YouTube Playlist for your stove.

  8. Leaving hopper lid open/unlatched: When the hopper is not sealed down tightly, air can be pulled through the hopper and feed system, reducing the amount of air through the fire. It is extremely important that the hopper lid be latched down tight while the stove is in operation. Airflow may enter the auger system and, in the event of a power failure or error shutdown, smoke can travel back into the hopper if the lid is not sealed down tightly!

  9. Improper fuel: Burning corn or cherry pits, for example, will cause a dirty burn because of the high ash, moisture, and sugar content.

  10. High altitude: Air density at high altitude can cause dirty burn, simply because of  the lack of available oxygen. In installations above 4,000 ft. above sea level, the exhaust should be expanded to 4" pellet vent pipe (suce as our AC-3100 kit), and the outside air intake should be run with 3" pipe. Click Here for info on High Altitude Installations