My new Upgraded Combustion Chamber Bricks did not come with any directions. Luckily I talked to Zenon from New Horizon. I did not know you are to put two regular fire bricks one on top of each other about 1 inch from the back wall of the combustion chamber before you slide in the new upgraded bricks. I thought you were to put one fire brick in front and one in back of the new upgraded bricks. Hope others that upgraded to the new combustion brick knew this. It is hard to see from the picture, but this is the configuration New Horizon has on its website