Two Chimneys - Sooty Smell coming back down the second one

ryandj

Hi
We have a small victorian terrace house, on the ground floor there is a front room and kitchen/ dining room (with bathroom extension). In both the front and dining room there is a chimney. Both are clear and usable, although we don't ever use the dining room one as there is no grate in it.

With the cold weather we have had the fire going in the front room quite a lot and I have noticed a sooty smell in the dining room which appears to be coming back down the chimney. Does this seem normal? I think it might be a bit dangerous? Is there any way to stop or fix it?

Thanks for any advice!