Hi, this whisky4 asking about what is the highest/and/or safest tempature that a chimeny in a 1924 house can handle,has no dampener,and was checked by chiminey sweep and was OK the back of the box has a slope to it,but I noticed that the bricks at the back appear to be worn off by the years of fires in fireplace it also appears that bricks are fairly thick as the fire box area goes outside of the house about 18 inches,also if I put a pellet stove in fireplace do I need to put a liner in flue,thank,s whisky4

I am sorry nobody answered sooner. There are questions I can help with, but often I leave them, hoping somebody will give a better answer than I can. If the material outside the fire brick is more masonry, and not combustible, I doubt the wear on the fire brick is a problem. I am not sure how hot a wood fire can get, but with a good draft, I have seen them consume thin aluminum. We had been burning wood long enough by 1924, that they should have known how to build a fireplace suitable for burning wood.

Don't know about the liner for the pellet stove. Others here should be able to say. The instructions for the pellet stove could be a good guide.

Note to moderator, better to delete https://www.askmehelpdesk.com/home-safety-security/fireplace-54379.html I decided to answer this one with the additional detail.