Performed a one system maintenance checking heating, checked inside units electrical and mechanical components, cleaned flame sensor and took amp draws, checked filter, checked 1st and 2nd stage heating. System is heating properly at this time. Noticed that the main drain for a/c was stopped up and dumping into secondary pan. Also noticed a possible roof leak by the flue pipe. Recommended getting a roof to look at. Homeowner wanted to hold of on uv and clearing drain line.