Long story short, my HVAC unit is 9yrs old with 1 year remaining under warranty. I started having issues with it running low on refrigerant after 2 years. My HVAC guy thought that the leak was coming from the expansion valve and replaced it that time with it being covered under warranty. A couple of years later, the unit can't keep up, so he comes out again, he can't locate a leak and refills it with refrigerant again. I had to call him out again last week for the same thing, he still can't locate a leak, but thinks it "may" be in the coil but he's not certain. This time charges me for 6lbs of refrigerant which was over $330.
So my question is this, if the leak is caused by a manufacturer defect, should I be charged for the refrigerant? I can handle paying the labor, I know manufacturer warranties don't cover the labor costs.
He also tells me that the unit will leak down again and that it would be between $700-$800 just in labor to replace the coil. I guess I'm struggling with paying that kind of money for a job, that he's not certain will fix my issue. Any HVAC guys have any advice or thoughts?

This post was edited on 4/8/24 at 5:03 am