I recently had a one piece flexibile 6" stainless chimney liner installed, the chimney is made of old brick with no liner and is 12" by 12" inside. The installer used an 18 x 18" stainless cap which sealed the top of the chimney off. When i use the wood furnace the outside of the chimney (which is exposed in the house) gets very warm and i was afraid that the cap was not letting any internal heat escape. Should i be concerned?
Thanks for any help