I have a wall-mounted AC unit. Specifically, a Fujitsu ASTG24LFCB. Recently water started leaking from the interior portion of the unit. I followed the instructions in this video to troubleshoot the problem. The process mainly involved tilting the unit up and checking for any issues/blockages in the drainage tube.
I didn't see any issues, but noticed that the drainage tube seemed to travel upwards after leaving the unit and entering the wall cavity. Thinking that could be a cause of the leak (because I assume the water can't drain uphill?), I started maneuvering the tube back through the hole in the wall to position it more in the downward direction. I was then surprised to discover that the drainage tube comes to an abrupt end. As in, it does this:
I don't see how this could possibly work? But not knowing what else to do, I fed the tube back into the wall cavity in the downwards direction, and the unit no longer leaks.
However, there's no longer any water being discharged on the exterior side of the wall. I think the reasons for that are obvious. Less obvious is an explanation for how the water ever reached the external drainage tube in the first place (which I'm positive it did, in the past)?
Is it common (or even valid) for an aircon to be installed like this? If not, how can proper drainage be restored? And what sort of damage will having the unit draining into the wall cavity cause, over what sort of timeframe?