Emmettculligan

I just finished making my first forge using 4 burners in a row, 18" apart coming into the side of the forge. Im using fire brick for the floor with the walls made up of 3 courses of brick and a steel fabricated top section with Kaowool. The dimension of the forge is 7' long by 2' wide by 2' tall. The problem is that I cannot seem to keep the actual buners lit when I put the lid on. I have exhast holes in both ends of the forge created with a missing brick. The flames blow out of these openings but I can tell that there is no flame at the burners themselves. Any advice is would be great.