If your property was constructed before 1966 it is strongly recommended that your chimney is lined with a liner suitable for a solid fuel appliance. After this date chimneys were typically constructed using clay or concrete liners. Depending on the condition of the liner and the ability to make a gas tight connection between the stove and the liner it may be advisable to put a new flexible stainless liner in. Another consideration is that the diameter of the clay liner may be too great for closed a solid fuel appliance like a stove.