Wood burning refractory bricks

[cmurray]

Hi all
We ordered a new refractory brick kit for our superior br-42 fireplace. After we installed them we have two small areas in each back corner where there is a small gap. It is no bigger than the end of my little finger but you can see the metal liner. Is it ok to use the fireplace? Should the areas be filled with something? I am attaching pictures and would love some feedback!

 

[DAKSY]

There is not a lot of heat that low in the firebox, so there’s not much to worry about. Ashes will eventually block those gaps after a couple of burns.