Is there a male dog in the yard where the A/C “compressor” (condenser) is located?
If you answered yes, you should consider erecting a fence around the unit to prevent catastrophic damage. Dog urine has a strong and very acidic content. If a dog urinates on the unit, the metal frame may be damaged over time but the delicate fins will start to crumble and deteriorate within a short length of time.
If the unit is running at the time the dog urinates the urine will be sucked into the inside and swirled around int inner casing causing faster deterioration. The damage is not always obvious, look for deteriorated fins with a white deposit that is corrosion, touch it with a screw driver and see if it crumbles. (this would not be a warranty issue)
If the damage is there, it is going to get worse even if the dog is removed.
The eventual outcome will be the replacement of the unit. (Replacing the exterior unit may involve replacing the whole A/C system)
A damaged or compromised unit will affect the air conditioning’s overall efficiently.
The fence to keep the dog away from the compressor should be placed approximately three to four feet from the condenser.
A gate should be incorporated into the design to allow service personnel access.
NOTE: The fence should be at least two feet high, and depending on the size of your dog it may have to be higher.
NOTE: The fence should be designed to allow air flow through it. A solid fence could impede the flow of air to the A/C unit.