Here we saw a oil furnace chimney that had completely plugged up with debris from trees, pieces of terracotta chimney liner and soot.
Use of a Chim Scan video camera down the chimney permitted to determine that there were many open joints inside this chimney. The only real alternatives were to completely tear down the chimney and start over, or put in a stainless steel liner.
This field visit followed the workmen step by step through installing a new liner to make this a safe furnace with a safe chimney. These guys are contractors from a company called Chiminee de l'ouest in Montreal.
Any time you think about a chimney you should think about exhaust fans in the house, because they could compete with each other. For more information, check out "Spillage Susceptible"