Pellet Appliances
There are a variety of types of pellet appliances used for heating with pellets, including pellet stoves and inserts. For more detailed information about pellet appliances, please read the Pellet Stove Fact Sheet.
Thinking of purchasing a pellet stove or insert? Learn more about the proper placement and maintenance of pellet stoves.
Pellet Appliance FAQs
 Appliance Placement
Operation
Maintenance
Enjoyment and Satisfaction
PLACEMENT
What factors determine appliance location?
For maximum enjoyment and heating effectiveness, a major living area where the family spends leisure hours and which provides heat flow to other areas is usually a strongly preferred location for the stove. The pellet heating professional considers the following factors when determining whether installation requirements can be met in the homeowner’s preferred location:
- Venting. Maybe limited by factors like obstructions above for vertical venting through the ceiling and roof, or by the distance to an outside wall for horizontal venting.
- Outside air for combustion, if needed. Must be drawn from an approved location.
- Space requirements. Must meet minimum clearances between the stove and combustibles. More space than the minimum required may be desirable to provide room for convenient operation and service.
- Electrical requirements. Proximity to a properly wired outlet.
What are my choices for floor protection?
The floor must be protected according to the pellet stove manufacturer’s instructions. The minimum size of the noncombustible floor protector is clearly specified in installation instructions. The choice of suitable material usually requires professional assistance, unless a suitable hearth is not already available in the home. Built-in appliances may require an additional layer of protection, such as an air space between the appliance and the floor protector.
What electrical requirements should be checked?
 The dealer or installer should check the intended appliance outlet for proper voltage, ground, and polarity. The electrical circuit to be used should have a properly rated circuit breaker. •Are there special requirements for mobile home installations? The model you choose must be approved for use in a mobile home. The U.S. Department of Housing and Urban Development (HUD) makes additional requirements for solid fuel burning appliances installed in mobile homes which are listed in stove manufacturers’ installation instructions.
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VENTING
What are the purposes of venting systems?
Proper venting is essential for proper appliance performance, dwelling safety, maintenance frequency and indoor environment. Pellet stoves produce little or no visible smoke after startup, but exhaust gases, fine ash and water vapor must be moved safely from the appliance to the outdoors without leaking into the house. The purpose of all vents is to remove combustion by-products produced during normal operation. For most designs, the exhaust is mechanical: a fan blows the combustion by-products out and pulls air needed for combustion into the fire. A few stoves operate without a combustion air fan and instead use natural draft both for exhaust and combustion air intake. Some heat also moves through the vent, making protection of nearby combustibles essential. The minimum clearance between the vent and combustibles, as specified in the vent installation instructions, must be met or exceeded to assure safety.
What materials and products can be used to vent pellet stoves?
The product specifically tested and listed for use with pellet stoves is PL vent pipe, labeled as tested to UL 641. PL vent pipe is double wall pipe; the stainless steel inner pipe that carries the exhaust products is separated from the outer wall by an air space. Pipe joints must be sealed gas tight to prevent exhaust products moving through the vent under pressure from leaking into the home. Stoves tested and listed with PL vent requirements cannot safely be vented with substitute materials.
Venting materials and products that MUST NOT BE USED TO VENT PELLET APPLIANCES include:
- Dryer vent
- Gas appliance (Type B) vent
- PVC (plastic) pipe
- Single wall stove pipe (unless clearly approved by the installation manual and local codes)
 Pellet fireplace inserts and freestanding stoves are often vented into existing masonry and factory-built fireplace and woodstove chimneys (Figure 8). The chimney should be inspected before installation to ensure that it is clean, mechanically sound and meets local safety code requirements. The appliance manufacturer’s installation instructions may require relining the chimney with an approved metal liner, pipe or PL vent. Vents or grilles on the face of factory-built fireplaces which provide cooling air to the outside jacket of the fireplace must not be blocked. Cleanout access for future maintenance should be considered.
What are my options for venting layout?
Mechanical Exhaust:
 Sidewall horizontal venting (Figure 9). Invariably the least expensive venting system. Disadvantage of potential smoke spilling into the house in the event of a power outage or component failure, or house depressurization (see discussion of next question). Horizontal vent with backup vertical venting (see Figure 10). Preferred horizontal method that avoids venting problems associated with unexpected appliance shutdown. Vertical venting through the ceiling and roof (Figure 11). Has the advantages of keeping vent gases warm and of providing natural draft to prevent problems in an unexpected shutdown.- Venting into existing chimney (see Figure 8). Stove manufacturers provide recommendations for venting into masonry and factory-built chimneys, which may include partial or full chimney relining.
- Natural Draft: All vents for appliances designed without mechanical exhaust fans must meet stove manufacturer’s requirements for minimum draft and must terminate above the roof.
Besides appliance requirements, what other factors may be considered in specifying pellet venting systems?
The following factors may play a role in the designation of the venting system:
- Altitude: High altitude installations, generally higher than 2500 feet above sea level, may require special venting options to provide adequate combustion air and/or draft.
- House Pressure: Extremely tight house construction or strong kitchen, bath or other exhaust fans may create a negative pressure within the home that decreases venting effectiveness. May necessitate an approved outside air source.
- Windy Conditions: Unpredictable effects of high winds or prevailing wind conditions may necessitate the addition of vertical venting that extends above the roof and/or special termination caps.
- Cleanout and Maintenance: The venting system must be designed with normal maintenance in mind.
How should pellet venting components be assembled and joined together?
Appliance manufacturer’s instructions should be followed closely regarding sealing joints and seams, particularly of pressurized mechanical exhaust vents. It is imperative that they be gas tight so that they cannot leak. Proper application of an approved sealant or sealing band is typically required. Appliance manufacturer’s instructions for pipe sealing which exceed vent manufacturer’s instructions must take precedence. You can get a sense of what heating with pellets involves through an introduction to the principles of operation and the reasons for maintenance that you will come to understand as an experienced operator.
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OPERATION
What’s a good starting point for learning to operate a pellet stove?
The rule here is “Before all else fails, read the instructions.” Operating a pellet stove is not difficult, but it is a new technology that calls for basic knowledge. Training videos accompany some stoves, and hands-on demonstrations are offered by many dealers and installers.
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).
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MAINTENANCE
What are the routine things that I do to keep my stove working right?
Routine maintenance tasks are essential to peak stove performance:
 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.
 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.- 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: Cleaned with glass cleaner, when the glass is completely cool, on stoves with effective air wash systems. May require more vigorous methods on others. Should the alignment be this way (over to the right)
- Hopper: Checked for accumulated sawdust materials (fines). Fuel in the hopper and auger tube should be emptied occasionally to prevent auger blockage by fines.
What are some of the more advanced maintenance tasks?
Cleaning the venting system is usually performed by professionals (see below), 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 professional maintenance and repair services will I need?
Most pellet stove owners depend on professional service for cleaning and preventive maintenance on at least an annual basis. Many dealers offer service plans that offer reduced costs and convenient scheduling. Cleaning and maintenance services usually performed include:
- 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.
Many manufacturers now offer low-cost, high-value extended warranties on electrical components. You can also benefit from professional advice that helps you improve stove performance and convenience with operating tips or fuel information.
How do I select a service technician?
Finding competent in-home service should really be part of the buying decision, since service is needed at least on an annual basis. Many stove shops and service technicians offer a service plan that specifies a service schedule, what is covered, travel costs and other details. One way to assess service record is to ask for references. Another is to look for technicians who have taken the national exam to become certified by the non-profit HEARTH Education Foundation.
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ENJOYMENT AND SATISFACTION
What will I like about heating with pellets?
Experienced pellet burners reap rewards for shopping and planning carefully and learning to operate and maintain their pellet heating system. They understand that pellet stoves contribute a dramatic improvement in convenience to the long tradition of the hearth. The fuel itself is easily and cleanly stored and handled in bags. A single loading of a pellet stove can provide long hours of warmth. Pellet stoves also provide a special comfort associated with wood burning. The combination of fans delivering warm air currents and the direct comfort of radiant heat provides special satisfaction on a cold winter day. The heat provided is even and constant, due to the automatically regulated fuel feed responding to owner settings. Pellet stoves also offer strong environmental benefits; pellets not only reduce dependence on finite supplies of fossils fuels like oil and gas, but they also put to good use materials that would otherwise unnecessarily and expensively add to our waste disposal problems. In addition, pellet stoves burn very cleanly and offer the lowest emissions of unwanted pollutants of all solid fuel burning appliances. Burning biomass pellets offers convenient heat delivered with environmental concern.
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