Pellet quality is important, please read the following: Your Wolf Steel Ltd. Pellet Appliance has been designed to burn premium hard or soft wood pellets only. Do not use any other type of fuel such as fire logs or fire starting pellets. The performance and heat output of the pellet appliance is directly related to the quality and moisture of the pellets. Store pellets in a cool dry area to prevent moisture absorption. If the fuel does not comply to this standard the appliance may not operate as designed. We recommend the use of premium grade (1% ash content) for longer appliance life and less frequent cleaning.