Pellet Stove Ash Pit Conundrum: Navigating The Heat Beneath

Pellet stoves are efficient, clean-burning home heating appliances that use compressed wood or biomass pellets. While they are easy to operate and maintain, they can occasionally run into problems, such as a build-up of ash in the burn pot. This can be caused by various factors, including insufficient airflow to the fire, dirty internal components, low-quality pellets, incorrect stove settings, and a faulty ash pan gasket. To prevent and fix this issue, it is important to ensure adequate airflow, clean the stove and its components regularly, use high-quality pellets, adjust the stove settings, and replace any malfunctioning ash pan gasket.

Pellet stove burn pot overflowing due to insufficient airflow

Pellet stoves are highly automated home heating appliances that are considered to be one of the most efficient solid fuel-burning systems. However, they can sometimes present problems, such as the burn pot overflowing. Here is an in-depth look at why insufficient airflow may cause your pellet stove's burn pot to overflow and what you can do to address this issue.

Insufficient Airflow

The fire in your pellet stove requires adequate airflow to burn correctly. Insufficient oxygen in the furnace will cause the pellet to fail to burn properly, resulting in a slow-burning stove and an overflowing burn pot.

Causes of Insufficient Airflow

• Blocked air inlet in the burn pot
• Faulty or leaky seals
• Air-to-pellet ratio imbalance

Solutions to Insufficient Airflow

• Clean the burn pot's holes and remove any blockages from the air inlet.
• Ensure proper burning of the pellets.
• Repair or replace any faulty or leaky seals in the burn pot.
• Adjust the air-to-pellet ratio to achieve the appropriate balance.

Other Common Causes of Burn Pot Overflow

While insufficient airflow is a primary cause of burn pot overflow, there are other factors that may contribute to this issue:

• Dirty internal components, such as the firebox, exhaust system's fan blades, air intake filter, vent screens, and vent dampers.
• Use of low-quality pellets that struggle to burn correctly and efficiently.
• Incorrect stove settings, preventing the stove from getting adequate combustion air.
• Accumulation of partially burned or unburned pellets in the stove due to the use of wet or unseasoned pellets or a lack of cleaning.
• Faulty ash pan gasket, failing to create a tight seal and causing the burn pot to overflow.

Maintenance and Prevention

To prevent burn pot overflow and ensure the efficient operation of your pellet stove, it is important to follow the manufacturer's recommendations for cleaning and maintenance. This includes daily, weekly, monthly, and seasonal cleaning routines. Additionally, using high-quality pellets that meet the manufacturer's standards will help minimize the chances of blockages and other problems.

Dirty internal components causing overflow

Dirty internal components are one of the main reasons why a pellet stove burn pot overflows. The dirty firebox, exhaust system's fan blades, air intake filter, vent screens, and vent dampers cause the overflow of the burn pot. Not cleaning the stove frequently causes a build-up of dirt, debris, and foreign objects within the stove, hindering its smooth running.

To prevent this, clean your pellet stove and its internal components daily, weekly, monthly, or seasonally as per the manufacturer's recommendations. Ensure the dirt build-up is not hindering the burn pot's easy operating process.

• Remove all ash from the pellet stove burn pot and from the front portion of the stove that houses the burn pot.
• Use the cleaning tool provided with the stove to scrape the burn pot and remove any built-up hard carbon deposits. If your stove didn't come with a cleaning tool, you can use a putty knife or a wire brush to scrape the burn pot.
• Clean carbon deposits off the exchanger tube by pulling out and pushing the lever in front of the stove several times.
• Vacuum out the front of the stove that holds the burn pot and remove any remaining ash.
• If your stove has a glass window, wash it using a fireplace glass cleaner.
• Clean the pellet stove blower motor and fan using a small paintbrush to remove dirt build-up.
• Inspect the gaskets around the door of the stove and clean any residue from the gaskets. Replace them if they are worn out.

Note: Refer to the stove's manual for instructions on how to clean a pellet stove burn pot and how often to clean it.

Using low-quality pellets

To prevent this issue, it is important to use high-quality pellets that are properly seasoned, stored, and handled. Additionally, regular cleaning of the stove's firebox or heat exchanger area is necessary to prevent excessive ash build-up. Ensuring proper airflow and draft in the stove, as well as adjusting the air-to-pellet ratio correctly, are also crucial steps to take.

It is worth noting that some pellet stove models, like Harman's Pellet Pro feed system, are designed to burn any grade of pellet fuel efficiently. These stoves have a bottom-up feeding system that burns each pellet completely, allowing for continuous heating. However, for most pellet stoves, using low-quality pellets can lead to operational issues and reduced efficiency.

Therefore, it is recommended to use high-quality pellets and maintain proper stove maintenance to ensure optimal performance and avoid issues like burn pot overflow.

Incorrect stove settings

Understanding Pellet Stove Settings

Pellet stoves have various settings that allow you to control the burn rate and heat output. The fuel feed control, also labelled as the "auger", determines the rate at which pellets are dispensed into the burn pot. The higher the setting, the hotter the fire will burn. The air inlet setting also influences the fire's temperature by allowing you to control how much air enters the stove.

Troubleshooting Incorrect Stove Settings

If your stove is set incorrectly, it may not receive enough combustion air, leading to an overflowing burn pot. To correct this, adjust the blower trim to half a turn to fine-tune the combustion air. Ensure the stove's air combustion is properly adjusted to prevent the fire pot from overflowing.

Maintaining Adequate Airflow

Insufficient airflow can cause the fire to burn incorrectly due to a lack of oxygen. This can be caused by a blocked air inlet in the burn pot, faulty or leaky seals, or an imbalance in the air-to-pellet ratio. To resolve this, clean the burn pot's holes and remove any blockages from the air inlet. Ensure proper burning of the pellets and adjust the air-to-pellet ratio as needed.

Cleaning and Maintenance

Dirty internal components, such as the firebox, exhaust system fan blades, air intake filter, vent screens, and vent dampers, can hinder the stove's performance and lead to an overflowing burn pot. Regular cleaning and maintenance are crucial to prevent this issue. Follow the manufacturer's recommendations for cleaning and maintenance schedules.

Fuel Quality

Using low-quality pellets can also contribute to an overflowing burn pot. Ensure you are using dry, well-seasoned pellets that have been stored properly in a cool, arid place. Wet pellets or improperly seasoned pellets may struggle to burn efficiently, leading to overflow issues.

Accumulation of Unburned or Partially Burned Pellets

The constant accumulation of unburned or partially burned pellets in the stove can cause the burn pot to overflow. To address this, use high-quality, dry, and properly seasoned pellets. Avoid using excessive pellets beyond the stove's capacity, and regularly clean the stove to remove any unburned pellets.

By following these guidelines and making the necessary adjustments to your stove settings, you can help ensure your pellet stove functions optimally and avoid issues caused by incorrect settings. Remember to refer to your stove's manual for specific instructions and safety precautions.

Faulty ash pan gasket

A faulty ash pan gasket is one of the reasons for a pellet stove burn pot overflowing. The ash pan latch stops air from leaking and ensures the draft required for a perfect fire. Without a latch, an ash pan gasket fails to compress enough air. A defective ash pan door gasket fails to make a tight seal, resulting in the burn pot overflowing with pellets.

To fix this, ensure that your stove's ash pan gaskets are in good condition. Also, make sure that the unit is properly sealed with the ash pan latch. Replace the malfunctioning ash pan gasket if necessary.

Ash pan gaskets are available for purchase online. For example, the QuadraFire Mt. Vernon & Edge 60 Ash Pan Gasket (SRV7034-178) is a replacement ash door gasket for Quadra-Fire pellet stoves and fits the following models: Quadra-Fire Pellet Stoves: Mt Vernon AE, Mt Vernon AE Insert, Edge 60 Fireplace Insert, and Trekker Trekker Insert.

Another example is the Harman Door and Ash Pan Gasket (3/8" x 10FT): 1-00-00888-10. This gasket is also sold in 20' and 30' lengths. It requires either stove cement or RTV silicone to install.

To install an ash pan gasket, first, remove the old gasket from the door and scrape away any old glue, silicone, or gasket material. If using gasket cement, the metal groove that receives the gasket must be clean and clear of debris. Apply gasket cement to the entire groove surface in a thin coating and let it become tacky, which should take around 15-20 minutes. If using RTV silicone, apply a 1/8" bead of silicone into the groove. You do not need to wait for the silicone to set up, and your surface does not need to be 100% clean of debris.

Starting on the hinge side of the door, in the middle, between the hinges, lay the gasket rope into the groove. Do not stretch the gasket as you go. Overlap the start and endpoints by approximately 1/2" and cut the length of the gasket. Tuck the ends together. Close the door and leave the stove at room temperature for 30 minutes for the adhesive to set up before starting the stove.

Frequently asked questions