Small buck-shot looking holes in A coil
This will be the 3rd consecutive year that I have had to replace the A coil for my AC unit. It seems 'something' is eating away at the copper coils. My AC rep showed me by running green die through the system and putting on goggles. It looks like someone shot my ac coil. The unit is in my unfinished basement. My washer and dryer and also there, but have no issues. The only thing wehave found is the cold water copper pipes are black, which we have researched, and the plumbing is grounded correctly.
The unit was replaced last July, ran the remainder of 2013. I turned it on May 29th and it ran fine until July 12th. The is the 3rd year this exact same thing has happened.
I did a radon test, which was negative. I don't know what else to test for, but there must be something. I trust my AC Rep and the product. He has been replacing with no charges to me under the warranty. Thought/suggestions?