Last night we experienced a severe rainstorm. The pump failure or high water alarm on my sump pump woke us up at around 4:00 this morning. I fixed the problem, but I'm not sure what was wrong, why what I did worked, or if I have to do anything further.
The previous homeowners had this brand and model of sump pump system
installed in our house when they owned it. My next-door neighbor has lots of wet basement problems; our houses were built on top of a natural spring. He told me that the previous owners had had that system installed because they often had "knee-deep" water in the basement. (This fact was not disclosed when we bought the house. I'm fairly sure pre-purchase disclosure of problems a homeowner experienced and how they solved them to a potential buyer is a state law here, but that's another issue entirely.)
We've owned the house for just over three years now, and both the basement and the crawl space have always been completely bone dry, even during the most severe of storms and during power failures (including one large snowstorm this past winter and the resultant power failure which lasted almost three days).
Normally, during a rain or snow storm, if you are in the basement or in one of the ground floor rooms immediately above and nearest to the sump pump, you will hear the pump cycle on and off every so often; more frequently during heavier precipitation, less frequently during lighter precipitation. During power failures, the pump failure / high water alarm will sound continuously until its 9V battery runs out and I have to replace it. This is an annoying, loud, ear-splitting alarm which can be heard from anywhere in the house.
Last night we did not have a power failure, though we had very heavy rainstorms overnight. My wife and I woke to the sound of the pump failure/high water alarm sounding at around 4:00 am.
I went down into the basement to investigate, and I did not hear the sump pump operating even when I was right next to the pump. I skim-read the manual, which lead me to suspect that the DC backup battery (a huge, presumably 12V monstrosity about three times the size of a car battery) had died and needed a recharge. I have not had the system inspected and maintained annually as recommended in the manual. The manual seemed to suggest that a recharge might become necessary -- though I am not sure why, as the system has a built-in battery charger/tender for the backup battery.
However, since we were not experiencing a power failure, I was at a loss as to why the system was trying to run off the backup battery anyway. Taking a complete guess, I unplugged the two plugs from the outlet and plugged them back in.
The pump immediately turned on, and the charging light for the backup battery turned red (indicates the battery is being charged) as well. After a few seconds, the alarm stopped sounding. The pump stayed on continuously for at least 15 minutes. Within the first two minutes, the charging light for the backup battery turned from red to green (indicating the backup battery is fully charged). Once the pump shut off it was back to normal operation for a heavy rainstorm: I could hear the pump turn on for a few seconds every three minutes or so. I went back to sleep.
(Later) In the morning, when I woke up to get ready for work (and it had stopped raining), I checked the manual again. I found some wordage to the effect of, "remove this cap and check the water level using a flashlight. If it is less than six inches from the top, immediately call to have your system serviced." I did as suggested, and the water level was much more than six inches below the top. So does that mean I don't have to call for service?
I'm wondering why the simple act of unplugging the pumps and plugging them back in again fixed the problem. What happened? What was wrong? Should I be worried? Do I need to find what contractor the previous homeowner used to install the system (they gave me very good records on who did what work to the house and when) and have them come out to take a look at it?