The home where I've lived for the past 18 years is built on sandy soil, with concrete blocks forming the basement walls. It's about 55 years old. There is a slight downward slope away from the house and I never have leakage of rain water into the basement unless I neglect to clean out the window wells. The basement has only one visable floor drain. It is next to the furnace and hot water heater and is very slow. The run-off from the humidifier will cause it to fill up and form an increasingly large puddle after only a few hours. So I have to keep the water line into the humidifier 3/4 closed. I've had this drain roto-rooted and power- rodded, but the line was impassable after about 25 feet. This floor drain would quickly be overwhelmed by significant water in the basement, say from a broken pipe or water heater. I want to avoid installing a sump pump, partly due to expense, but also because I don't want my basement floor chopped up to make basins or canals. Now here is the actual question: The floor outside of the furnace room is covered with linoleum tiles. Isn't it very likely that there's a floor drain under those tiles somewhere? And if so, might it perhaps still function? If I could find it, I could run a hose into it to test it out. So I rented a metal detector this morning, but it registered what had to be false positives over the entire surface of the linoleum. I kept adjusting the sensitivity, but to no avail. Any suggestions would be much appreciated.
I have found very few basements with more than one floor drain and doubt that you will find a second floor drain. Here are some other options:
Your experience about the windows wells is right-on. Most basement moisture problems should be solved from the outside by controlling roof and surface water runoff. So you might want to start by increasing the size or improving the configuration of the window wells.
There are some small condensate pumps that are used with furnaces etc. You maybe able to use one of those for you de- humidifier. Such pumps don't require any concrete cut