I am an amateur, so ask all the stupid questions you need to.
I have a submersible sump pump in my basement. It mostly works; however, from time to time, I have to tap the switch housing (I don't know what else to call it. I mean the little box that appears to house the connection between the float/switch and, I'm guessing, the motor) in order for the pump to turn on. The float appears to move freely up and down, but, of course, I can't tell when I have to tap the switch housing whether the float also suddenly rises to engage the switch.
If I pull the float up by hand, the mechanism works fine. When I tap the switch housing, the pump successfully gets rid of all the standing water, even if that takes several minutes.
This pump is about 2-3 years old.
That's as much as I know to tell you up front. I'm looking for possible common causes, simple DIY tricks I can try to improve the situation, and signs that I might need to replace the pump. It appears to work in general, but, of course, I'd like it to be more reliable than this. Which seems more likely: the float is occasionally sticking and not rising and not engaging the switch or there is something loose between the switch and the motor that a light tap jostles just enough to make it work? or is there something else entirely I need to look at?
Update: I did some simple testing today, and the float appears to work well. I filled up the pit both quickly and slowly (with a hose pointed away from the float) and the float rose in the pit every time. I tried spraying some water at the underside of the housing where the float slides up, in case that knocked loose some dirt or muck that might have been occasionally getting in the way. When I let the pit fill slowly over several minutes, the float appears to rise and all seems well. Again---at least as much as my amateur eyes can figure out. I'm happy to take more suggestions for what to try, either to find the cause or to rule other causes out.