Tip on Drain Lines
https://stephenxpta941.wordcanopy.com/posts/indoor-air-quality-problems-that-point-to-ac-repair-in-north-fort-worth-and-how-comfort-experts-can-help-4
Tip on Drain Lines Tip for anyone with an attic air handler: check the secondary drain pan a couple of times each summer. Ours had standing water I never would have spotted otherwise