Replacing the heat exchanger

Had a preventive maintenance check done on the AC system for the house and they tell me the big heat exchanger thing outside will need to be replaced soon. The cooling fins have a lot of calcium build up on them and are starting to corrode away at the bottom. The guy who came out to do the inspection said it would probably last through the season but wasn't optimistic about it lasting much longer.

Given that I'm sure they'd love to sell me a new unit, I take his forecasts with a few grains of salt. It's pretty clear though that the unit needs to be replaced fairly soon as in within the next year or two.

So that looks like about $4000-6000 to replace. Ugh.

My unit must suffer from something location related, because my neighbours' units on either side don't seem to be suffering from the same problem. Their units look pretty clean and almost new compared to mine.

I wonder if spraying the fins down with CLR would help clean up the calcium buildup. I'm a little worried there might not be much left underneath the calcium and I'd end up making things worse. Spot test.

Time to do some research on these things and figure out what I need.