How Much Clearance Between a Pellet Stove Auger & the Chute?

Components

• Pellet stoves store wood pellets in a hopper, from which they empty into a fire pot inside the stove for burning. The mechanism that moves pellets from the hopper to the stove consists of two chutes and an auger. A pellet stove's auger is a metal shaft with a flat spiral wrapped around it, resembling a large screw. The auger captures pellets in the hopper and raises them through the first chute before allowing them to fall into the second chute, which is hollow and leads to the fire pot.

Clearances

• The clearance between the sides of a pellet stove's chute and the auger inside varies from one model to another. But it is generally just a fraction of an inch. The space between the auger and the chute must be small enough to prevent pellets from falling back down into the hopper. Yet it must also be large enough to allow dust from the pellets and foreign objects to fall through without jamming the mechanism. The auger and chute that come with a new stove are calibrated to work together, meaning that these clearances don't generally become concerns for users.

Potential Problems

• If the clearance between a pellet stove's auger and chute is too large, only some of the pellets will reach the top of the chute and empty into the fire pot. This means that the auger will need to run more often and for longer periods of time to keep feeding the stove fuel to maintain a consistent room temperature. If the sides of the auger are too close to the walls of the chute, the sawdust from pellets will collect and prevent the auger from turning smoothly. This places excess strain on the motor and may slow its motion, causing the same problem with fuel delivery as a clearance that is too large.

Replacing Parts

• If you need to replace either the auger or the chute for your pellet stove, attempt to find an identical replacement from the stove's manufacturer. If this proves impossible, consider both a new chute and a new auger that are designed to work together. If you only want to replace one component, make sure that you can view down the chute with the auger installed and see light all the way around the auger. This ensures that there is enough clearance for the auger to spin freely. Place the assembly in the hopper or a pile of pellets and turn the auger manually to make sure it raises pellets without allowing them to fall back through an overly large clearance.