Fire bricks line the floor and walls of your wood stove to protect the steel from excessive heat. The lifespan of a wood stove would diminish immensely without protection from the bricks. Without the fire bricks, the excessive heat of the exterior steel on the wood stove could set fire to combustible objects around the stove. You should replace broken fire bricks immediately with bricks made from the same material and the same size as the original bricks. Replacing the broken bricks extends the life of your wood stove.
Allow the fire in your wood stove to burn down, and let the embers cool. Clean the cool embers from the stove. If you haven't burned a fire within three or four days, you can use a wet-dry vacuum to remove the ash from your wood stove.
Pull any cracked or broken fire bricks from the wood stove. Pry the bricks out with your fingers or gently pry them up with a flat-blade screwdriver. Grasp the broken or cracked bricks, and pull them from the wood stove.
Clean the space created when you removed the broken or cracked bricks. If the wood stove is cool enough, vacuum the debris from the area with your wet-dry vacuum. Make sure you remove any broken pieces of brick that may have wedged beneath the adjacent bricks. Use a small wire brush to help get all the fragments out.
Insert a replacement fire brick into the space that was occupied by the original brick. Use bricks made from the same material that are the same size as your original bricks.
Place a wood block over the new fire brick. Gently tap the wood block with a rubber mallet to wedge the brick into the space along the floor or wall of the wood stove.
If you are unsure of the type of brick your wood stove requires, check with the manufacturer.
Written by Cecilia Harsch; Updated December 10, 2018 | Source https://homeguides.sfgate.com/replace-fire-bricks-wood-stove-39412.html