Rheem AC Unit - Air Handler Full of Mold
I live in central Texas and we have a Rheem AC unit. I recently discovered that the original installer failed to include a cleanout on the system, causing the drain to back up and water to pool in the air handler. The insulation inside the air handler is ruined, full of mold, and the mold has spread down the duct board plenum. Thankfully, it hasn't reached the flex duct yet. I work in construction, but I'm not an AC expert. When the cooler months arrive, I'd like to replace the plenum and remove all the insulation from the air handler, but I'm unsure how to disassemble the air handler and what the process involves.
After seeing the mold in the pictures, my wife thinks we should replace the entire system with a new AC, but I don't believe that's necessary since the unit is still functioning well. Do you have any advice on removing and replacing all the insulation inside the air handler? It seems like I'd need to remove the blower motor to access the insulation underneath. I'm very handy, but is this a job I should hire a professional to handle? I'm also concerned about hiring someone and ending up with poor-quality work again, as the original installation was done incorrectly.