Every wood burning stove with fire brick liners will need to have its bricks replaced on a regular basis to keep the stove performing at optimum
Firebrick - Earthcore
Napoleon®
Firebrick - Earthcore
Fireplace Parts & Accessories - Bliffert Lumber and Hardware
Hargrove Replacement Refractory Panel, 23.5 H x 39.5 W x 1 thick
US Stove Firebrick Universal Fit (6-Pack) FBP6E - The Home Depot
Make sure that your unit is functioning properly with these US Stove Firebricks. They're compatible with any USSC model except for the 3500 and 3700
US Stove FBP6E FireBrick, 6-Pack
US Stove - Fireplace Accessories - Fireplaces - The Home Depot
US Stove FBP6 Firebrick, Pack of 6
Firebrick - Earthcore