Excessive rust on evaporator coil?
This picture is of my Carrier 3.5 ton AHU. Its located in my attic, and I live in San Antonio. I have an electric heat pump outside. Its just over 5 years old, and appears to be just out of warranty. I opened up the panel to the coils because there as water dripping from the bottom of the unit into the secondary drain pain, which I assumed was because the primary drain pan must have been overflowing because the condensate drain line was clogged.
I have cleared out whatever clog there was in the main condensate drain from what I can tell. But now my question is, should I replace these coils because of the excessive rust? I assumed the rust is what caused the clog in the condensate line. Or can I just have someone come clean them?
I had a tech out here and he quoted me a cost of $ to replace the coils and [COLOR="Red"]$[/COLOR to replace the whole AHU. Seemed fishy to me. I've asked around to some folks I know who do this kind of work and they said a coil replacement is more like [COLOR="Red"]$[/COLOR for this size unit.
So what do you all think? Replace coils? If so, should I replace with aluminum coils so they don't rust?
Thanks, I appreciate any and all inputs.