I was hoping someone here could help me identify the part that has 2 vertical cracks in the attached image. I think it may be part of the "bypass" system, but I'm not sure. Also, I really need to know whether this is a bad (possibly dangerous?) flaw and if so, how I should go about fixing it. Maybe patch it with stove cement? In the image, the upper firebricks and retaining bars have been removed to see everything better.
Thanks for your help!
Thanks for your help!