I have a 5 yr old house. I noticed the aux drain line was dripping over my guest room window. I checked the main drain line near the exterior unit and it wasn't clogged. I then go upstairs in the attic to see and the main drain line was leaking at the connection to the unit. I've gone to Home Depot to put some sealing putty the plumbing rep there told me would work but when i got back to put it on I noticed another leak from underneath the unit itself into the drip pan. Only thing I've found is about 20 yr old units doing this but not a 5 yr old system. Does this warrant a complete air handler replacement?
R&R Remove and Replace and worn, damaged or broken parts with new!
If your unit is only 5 years old than more than likely it is something else going on... please do not suggest to repair man that you think the air handler needs replacement or they might jump on that and tell you YES and take your money!
Kai