Sorry misunderstood you and yes waiting for rain is for the benefit of those below. Unfortunately the balcony does not have a suitable drain and ledge. Any water applied will just go straight over the edge!maneo wrote: Was not suggesting you rely on the rain to clean the fins.
Thought that "waiting until it rains" was so the people in the "23 floors below" would close their windows and take their clothes in before you start spraying your unit.
However, this should not be an issue if your balcony has a proper drain and a ledge to keep the dirty water from spilling over.
It really shouldn't matter that you are spraying from the outside.
Other than the fan, there really shouldn't be anything "inside" to worry about.
A cleaning solution should help the dirty water flow down and over to the drain.
Keep the spray pressure low and the angle close to parallel with the fins.
The fins are delicate and work best at transferring heat when they are not bent or damaged.
By the way, last set of compressors I cleaned using a hand sprayer.
It was a little tedious, more so because I had to keep refilling the sprayer from a bucket of water, but the compressors were just way too far from any threaded faucet to use a hose.
I do have the water supply close enough to use a hose but I am still inclined to try steam cleaning. I own a steam cleaner and it will be way less messy especially with a dust sheet or two down. I would not have to wait for rain or risk the wrath of those below.