The photos of condenser coils above and below are just a couple of examples of the damage your cute and hairy best friend can do to an air conditioner condenser coil. This is caused by a dog consistently urinating on the condenser. Canine urine is very acidic and over time rots away the aluminum fins. This damage affects the cooling ability of the system. We ultimately replaced the unit above once it began to leak. This can be avoided by installing a wooden fence around the new unit so now all the customer has to worry about is replacing a few boards every couple of years instead of a new condenser coil!
This appears to be strictly related to male dogs. If you have a male dog or two, you may want to put a fence around that unit to protect it. Just be sure to leave plenty of room around the condenser for ease of maintenance! Another good practice would be to rinse the coil with the hose at least once a week to keep it clean.