Wood Pellet Stove Guide How does a wood pellet stove work? Wood pellet stoves work similar to traditional wood burning stoves but use wood pellets as the fuel source. Pellet stoves have a hopper where pellets are stored and are automatically fed from the hopper to the burn pot (see above illustration). The size of the hopper determines how frequently you need to add pellets. Heat-exchange tubes: Sends air heated by fire into room Hopper: Stores pellets to be burned Convection fan: Circulates air through heat-exchange tubes and into room Burn pot: Holds pellets for combustion Auger: Feeds pellets from hopper to burn pot, where they are ignited Ash pan: Collects remains of unburned pellets Grille: Allows room air to be pulled in by convection fan Intake vent: Pulls outside air into burn pot Exhaust vent: Takes away combustion gases Combustion fan: Pulls in outdoor air and exhausts gases
Pellet wood stoves are generally used to heat zones or isolated areas in your home. They must be vented to the outside, either up a chimney or vented to the outside through a wall. If the installation is possible, you may decide to add a pellet stove to the area of your home where you spend most of your time during the winter months. Pellet Information Wood pellets are best when they are all wood and no paper or cardboard products are added. The best measures of pellet quality are (1) heat output, (2) ash content, and (3) moisture content. The easiest way to check the quality of a wood pellet is to smell it. There should be a clean, fresh wood scent. If you notice any strange odor it is a clear indication of a by-product in the pellet. When purchasing pellets, buy one bag at first to try before you purchase a large quantity. Inexpensive pellets may crumble and clog the auger. In general, top-fed stoves require high quality pellets while bottom-fed stoves can often use pellets of lesser quality. How often you must add pellets depends on the size of the hopper and how hot you run the stove. A pellet stove with a small hopper may need to be filled twice per day, while stoves with a large-capacity hopper can run hot for four or five days before they need to refilled Sizing the pellet stove for your application is done by a qualified installer who will calculate the area/living space where the unit will be placed and size the stove accordingly. Quantity of pellets needed can also be approximated by that professional using heat calculations with details of the area of placement. How do I store my pellets? Indoors: It is recommended to store inside in a dry area free from flooding, mold, and excessive humidity. Restacking the bags on the manufacturer s pallet and cardboard slip sheet is a great way to raise your pellets off the ground and protect them from moisture. Outdoors: If you don t have room to store your pellets in the garage or basement, the next best thing is a shed or shelter in a high, dry place. If you store pellets outside, carefully inspect your fuel when it arrives and repair any rips or holes in the plastic shrouding with water proof tape or additional layers of plastic. It is strongly recommend adding an additional, securely fastened tarp over your skids to protect from water and from any birds or squirrels that may puncture the plastic. Operation of a Wood Pellet Stove Pellet stoves are general used to heat zoned areas. This is the most practical use because you are able to heat an area of the home that you spend the most time in. The stove is designed for continuous operation and is most efficient in the Low or Medium settings. Check the stove during the day for fuel quantity and general operation status. Always look through the glass at the firepot and the area above the pot. If the stove is adjusted properly with good quality fuel, the pot will be approximately one third full of coals and the surrounding area a light tan color. The color indicates clean combustion. If the firepot is more than a third full, or the area is black and sooting, the firepot needs to be cleaned. How do I start a fire? Small dry fuel (pellets) and combustion air (provided by a fan on most designs) make startup easy. Operating instructions accompanying the stove give the specific steps to follow. Manual ignition stoves call for the owner to apply an approved gel or solid starter material (no liquids), light the pellets, and monitor the fire to see that the fire catches and the flame gradually grows. On automatic ignition stoves, pushing the start button feeds pellets to the burn pot and heats the self-igniter device. What if the stove doesn't start properly? A safety device monitors startup and stops fuel feed if operating temperatures are not reached within a specified time period. If startup fails, the operator should first make sure that the hopper has fuel and that fuel is feeding into the burn pot, and then attempt to restart the stove. Repeated failed lighting cycles indicate the need for maintenance or professional service. What do I do after the stove starts? After control panel or air inlet adjustments and a quick performance check, the stove is set to provide hours of even, comfortable heat. Stoves equipped with a remote wall thermostat respond to a set room air temperature by cycling on and off or by cycling from a low to high burn, depending on stove startup design.
What are signs of performance problems? Properly operated and maintained pellet stoves experience few, if any, problems. Most of pellet stove operation is automatic, but sometimes combustion air adjustment is needed. A lazy, orange, sooty flame or dark smoke coming out of the vent (after startup and before shutdown) may indicate the need for more air. An overactive, "blow torch" flame calls for less air. Performance problems are more likely to be caused by neglected maintenance than by regular operation. Lazy flame, dark smoke, unusual sooting of glass, unexplained smoke spillage and reduced heat output all point to the need for maintenance of appliance components and/or the venting system, or for remedies for house depressurization. Problems related to mechanical failure usually results in safety switches shutting the appliance down. Appliance shutdowns may, however, indicate nothing more than owner forgetfulness (empty hopper) or hurry (improper startup), or intermittent power failure. Unexplained, repeated appliance shutdowns call for professional advice and service. How do I shut the stove down? Shutting the stove down is typically a matter of simply setting the control to the Off position according to operating instructions. The fuel feed stops delivering fuel right away, and after the stove cools sufficiently, all motors and blowers cease operation. The stove should NOT be shut down by unplugging the power cord What happens in an unexpected shutdown such as a power outage or component failure? Although fuel feed stops in a power outage, the pellets in the burn pot may continue to burn or smolder. The duration of this condition can vary with appliance design from a few minutes to an hour or more. The resulting smoke and hot gases rise, seeking the path of least resistance. If the exhaust vent does not have vertical sections to provide natural draft, smoke may spill into the home (Figure 14). Annual Maintenance Maintenance of a Wood Pellet Stove Within nine to twelve months after the stove is installed, the installer is required to return to your home for an annual maintenance service call. This service call is part of the installation, but you will need to call the installer to make the appointment. Beyond the first year and before each heating season, have a qualified pellet stove/chimney professional inspect and, if necessary, clean your pellet stoves flue. Routine Maintenance In addition to annual servicing, pellet stoves need regular maintenance, which is mostly a matter of cleaning. This should take no more than about 15 minutes. A tool that makes this job relatively easy is a special ash vacuum (don t use a conventional home vacuum cleaner, the soot and ash can ruin it). What professional maintenance and repair services will I need? Emptying ash traps and cleaning exhaust passages behind the fire chamber. Cleaning and lubricating fans and motors. Cleaning the hopper and fuel feed system. Cleaning the heat exchanger system. Cleaning exhaust pipes and resealing the venting system if needed. Verifying and adjusting the stove settings with proper gauges and meters. Mechanical and electric components may eventually wear out and need repair or replacement. What are some of the more advanced maintenance tasks? Cleaning the venting system is usually performed by professionals but can be tackled by the handy stove owner with thorough knowledge and the right equipment. Motors and fans need occasional cleaning and may require lubrication. The wrong lubricant or wrong amount of lubricant can damage components. Some components which call for removal for service require the replacement of a gasket. Additionally, gaskets for the fire chamber door, ash pan door and hopper lid (on some designs) may need occasional replacement to assure a tight seal.
What routine (but essential) maintenance can I perform to keep my stove working well? Burn pot - (Figure 15): Checked daily and cleaned periodically to keep air inlets open. Frequency of cleaning depends on fuel type, grade, and content. Ash drawer - (see Figure 15): Emptying recommended before starting new fires and occasionally during stove operation. Frequency depends on fuel and stove design. Typically once or twice a week, but monthly in some new designs. You may empty the ash drawer while the stove is running if needed. Heat exchanger - (Figure 16): On some stoves, simply a matter of moving a rod that scrapes the tubes inside the stove. May require professional service on others. Check owner s manual for specific instructions. Ash traps - Chambers located behind the fire chamber which prevent excess fly ash in the exhaust from exiting the stove. Easily accessed for ash removal by owners in some designs; on others, professional service is required. Glass - On cool glass, clean both sides with a commercial glass cleaner made for heated glass and a damp rag. You may also clean by dipping a damp cloth into the ash and rubbing it on the glass. Some models may require more vigorous methods. Hopper - Checked for accumulated sawdust materials (fines) and unused pellets in the hopper and auger every time you add pellets. Fuel in the hopper and auger tube should be emptied occasionally to prevent auger blockage by fines. Clinkers" - Look for these that form when ash melts and hardens. Clinkers can restrict air flow and upset the proper mixture of fuel and oxygen to the burn pot. Remove them with a special rake or ash tool made for this purpose. Soot build-up - This can happen on the inside surfaces of the stove. (As little as 1/10 inch of soot can drop the heat transfer by 50 percent.) Clean the soot off with a wire brush, but do not use the brush on the glass doors. Check the flame if it is orange or dark instead of bright yellow or white, it is time to call in a service professional.
Every stove is different, and you will find some of the best advice in your stove manual. But whether you re burning pellets for the first time in a new stove, firing up your system at the start of a new season, or switching to a new brand of pellets or a new shipment, here is a quick reference guide for troubleshooting some common burn quality issues. The Problem The Likely Culprit The Solution Poor burn quality) Dirty stove Clean your stove according to your manufacturer s recommendations. Blackened glass Burning on low Adjust heat setting to medium or medium/high. Excessive clinkers Airflow leak Clean all vents, check and repair/replace all gaskets, adjust damper or airflow setting. Trouble igniting Adjust air-to-pellet ratio by increasing air flow. Lazy or small flame Low heat output Sparks flying / embers in the ash pot Whole, charred pellets left in the burn pot Auger jamming / stove shutting down Excessive ash build up / whole, charred pellets in burn pot Long pellets Short pellets Adjust air-to-pellet ratio by increasing air flow and/or decreasing feed rate. Adjust air-to-pellet ratio by increasing air flow and/or increasing feed rate. Adjust air-to-pellet ratio by decreasing air flow and/or decreasing feed rate. Adjust air-to-pellet ratio by decreasing air flow and/or decreasing feed rate. Drop bags on the floor this can break long pellets into a manageable length. Reduce feed rate. Information by Woodpellets.com