I purchased a CL210 Megaflow unit in 1993 and have been very happy with the performance. At the time of installation I was advised that it could be sited in the loft for convenience. However, I was later advised that I would have to re-intsall the air gap at regular intervals which obviously makes the siting in the loft rather inconvenient. I note that the latest Megaflows have a baffle which maintains the air gap. Does this mean that the air gap never needs to be regenerated? I would also be grateful if you could advise regarding adding an expansion vessel to my Megaflow. Is this possible and would it do away with the need to regenerate the air pocket?