Fireplaces, Heating Stoves, Flues and Chimneys - Refractory panel damaged

The floor of our fireplace has a significant crack in the refractory floor panel. Is this cosmetic or more serious? What would happen if it was used in this condition?

I'm not an expert on this by any means, I didn't even know what those damn plates were called ( mine are ceramic ). I just had my fire flue cleaned and the guy who did it noticed mine was cracked on the bottom and the one in the back, and he said I should buy new ones, because they are there to reflect heat away from the thin steel behind them, and with the cracks the heat could get in and damage the metel or worse burning embers could fall through and ignite in a place I can't get to if it got out of controll. Hope this helps, I've been trying to find some place that sells them, but now that I know what there called, I might have better luck finding them.

It was years ago and I don't remember the name of the stuff but it was a refractory crack sealer in a tube that fit a standard caulking gun. It looked a bit like thin blue silicone sealant but was specifically for cracks in refractory. Once it was fired it was hard.

The stuff I used was from a commercial refractory company but similar products should be available in a well-stocked fireplace shop or at least they should be able to tell you where to find it. As long as all you have is cracks and not pieces missing there should be no reason to replace the entire refractory panels.

Thanks for the tip, I got a quote of $800 to replace them, they cost $150 a panel and weigh about 110 pounds, so the shipping is as much as the 4 panel kit, so I am going to look for that repair kit- thanks for the tip.