Folks,
The attached picture is taken by a phone I stuck right inside the condenser part of a window-mount air conditioner. The big solenoid-looking contraption in the centre of the image is what I'm wondering about. To its right is that rubber thing; I believe that if the water rises high enough to enter that hole in the top, it drains straight out of the unit (when viewed from below, that hole goes clear through the unit. IIUC, it is desirable to let the water build up so that it can evaporatively sub-cool the condenser.) I assume maybe the rubber thing on the right though is only there as a fail-safe in case the solenoid-looking thing fails to open.
So the solenoid-looking thing (the thing that I'm asking what it is), has a corresponding hole in the bottom of the unit, but that rubber cone bit is pressed quite firmly into that hole, thereby preventing any water from escaping. What I don't get, though, is that I am 99% sure there aren't any wires leading to the solenoid-looking thing, so it can't be a solenoid. So what is it, and how is it powered?
The only (totally speculative) theory is that it might be some clever contrivance that retracts the rubber cone when it gets below a certain temperature. I presume in cold weather, you don't want water hanging around and possibly freezing? I'd be impressed/surprised if it'd be such an issue that they would dedicate a separate line item/device for that, though.
(On the slim chance my guess is correct, I'd still like to know what the device is called.)