How I got more cold air
Posted to help others. I found some cold air coming out of rear ceiling light and on checking, a lot around ceiling vent/skylight where optional a'cond would go. Removed trim and found duct coming from front a'cond wide open and dumping air. Plugged with a rag and sealed with tape. Still have some leakage around vent from ceiling cavity! Got out IR heat gun and seems like there is a lot of air leaking into ceiling at some ceiling vents. If so, that is going to be a lot harder to fix. I found the best time to shoot ceiling temps is after a'cond has been running and just shut off. You can even follow your ducts as the ceiling is colder along the duct path. I figure this could be a common problem for Damons with only one a'cond.