Responded to emergency call for Trane XR17 system with water damage in ceiling. Diagnosed primary condensate line completely blocked with algae buildup, secondary drain pan overflowing. Cleared obstruction using compressed nitrogen at 100 psi, flushed with antimicrobial solution. Installed cleanout access and float switch safety cutoff to prevent future issues. Also corrected improper drain slope (was 1/16" per foot, now 1/4" per foot). Added condensate tablets to inhibit future biological growth. System now draining properly with zero moisture issues.