Hi, I've got an outside boiler in a small brink enclosure. It has a short open flue. I've heard that if a balanced flue is used, the hot exhaust gas warms up the incoming air, acting like a heat exchanger, increasing boiler efficiency. Is this correct? If so, what is the maximum length that I could use for a balanced flue? (The existing flue is about 700mm long within the brick enclosure.)
Thanks, JD
Thanks, JD