Condenser fin discoloration

This Lennox heat pump unit was mfg in 7/2006.

The fin coloring was different than usual. Mostly when I see the discoloration there is a male dog present and the problems are near the bottom. This was on upper and lower areas.

Any opinions ?

For a little background, original home 1979, and this area of home was add-on in appx. 2006. The inner evaporator for this system was mfg in 2008. Wonder if they didn’t match it when installed ?


I will venture to guess that it is moisture left over from a defrost cycle that had recently occurred and did not totally remove moisture before terminating.

The pattern is is inconsistent with anything else I can come up with.

Any chemicals nearby. Maybe a pool.
Did you touch the fins. They almost look like they would disintegrate if touched.

There was an inground pool in the yard. mmmm, the a/c was to the side of the pool 18 - 20 feet away. On around the corner (8’) and back about 20’ was the pump, filter, etc. Could the fumes from the chemicals have caused the discolor ?

Only if they were strong enough for long periods, I have seen that on many units and think it is mostly due to poor manufacturing processes.