Why is it, that every year on first start up, the stove pipe leaks? This year, it's at the bottom cap. I have had a faulty pipe from the start. After install, it didn't hold smoke on the inside. We called the shop and they told us they need to be siliconed together, although thats not what the manufacturer said. Then later, the shop told us the rope gaskets prevent the need for silicone. We ended up siliconing all the joints, but at least one leaks at start up. Why?