Yes woody is absolutely right it is the install i have a problem with not the stove. While the stove is not as efficient or clean burning as new ones the stove itself is not a safety issue but a direct connect is. Direct connects if the clay liners are sized correctly and you can seal the stainless into the clay would be just fine. But generally the clay is much to large and there is no way to seal the stainless in them. They are also very difficult to clean properly and there for rarely get cleaned thoroughly which is another safety issue.Perhaps an explanation to this statement would help. As to function, the stove functioned adequately when built, or do you mean that the stove was never acceptable as a functioning stove? Not a safe stove? Do you mean that with a direct connect chimney that it is not safe or that the stove is not safe as designed? Many of the old slammer stoves were the same stove as a non-slammer but just had a stove block off plate instead of a flange to connect it to a chimney. If you mean that in older stove is not as good as a new stove that makes total sense, just like all 20 year old cars are unsafe because they do not have the same safety standards as brand new cars.