Did I fix my sump pump? Was there even a problem?
June 5, 2014 10:17 AM   Subscribe

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?
posted by tckma to Home & Garden (7 answers total)
I see this happen to UPS units a lot. There are two things that can go wrong - the batteries will wear out over time and need to be replaced, and I think that is a bigger worry here. I'd keep a close eye on it, and look into maybe replacing the backup battery.

But, second, These systems are usually designed to occasionally test the battery and it failed, or the brains on the battery controller mis-read the battery voltage or some such and failed into an alarm state. When you unplugged it, you reset it and it was happy. It may reoccur, if the batteries are indeed going bad.

I would see if you can force another test or something and find out more definitively.
posted by Pogo_Fuzzybutt at 10:50 AM on June 5, 2014 [3 favorites]

Batteries on a float charge like that only last about 7 years. You should get a new one.
posted by flimflam at 12:30 PM on June 5, 2014

I would do a rundown test on the battery, as in unplug it from the wall and try and make the pump run off of it and see how long it lasts. If that seems fine, i'd assume it was a bad charge controller or a fault in the UPS type handoff circuitry that was just causing the pump to fail to run in general.

nearly all battery chargers, if you plug and unplug them will start charging again for a couple minutes. I'd only conclude the battery was toast if it actually didn't run the unit.

You could also just grab a crappy inverter, connect it to the battery, and plug in some small motorized appliance like an immersion blender and see if the battery runs it for more than like 10 minutes.

"About 3 times the size of a car battery" sounds like something along the lines, size wise, of an 8d truck battery. Obviously, you'd want to check in the manual and google the model number of the battery online and make sure it wasn't something weird or specific(just a truck battery? just a deep cycle marine? something not flooded but sealed/AGM specific to this application?). I'd figure it was probably a sealed AGM. One of those that size is going to be $$$, like, $800 probably. I'd absolutely make sure it was totally boned before i even investigated getting a new one.

Just from the damage i've seen one of these fucking up do to a friends house though, if i got to the "wtf is it the charge controller or the power controller" stage and the battery seemed fine, i would call a specialist in and pay him $80 or whatever to tell me what the hell was wrong. Because who knows, if either of those things are starting to go bad from corrosion or age or cold solder joints or ??? maybe the alarm won't work next time.
posted by emptythought at 2:56 PM on June 5, 2014 [1 favorite]

You should schedule that long-overdue maintenance call. A couple hundred bucks or whatever is WAY less aggro than a flooded basement.
posted by Johnny Wallflower at 5:53 PM on June 5, 2014

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?

Whatever the exact wording was, I'm fairly sure the import was that the water level should be no lower than six inches from the top and that the water level is an indicator for how much liquid remains in the big battery's cells-- so you do need to call for service.

I'd guess that the big back-up battery energizes a water level detector and also controls a relay that connects the pump motors to AC power when the level detector trips, but that the big battery was not strong enough to operate the relay, much less the pumps themselves, and so the pumps did not turn on. The mere fact that the big battery showed charged so quickly is a sign that it's bad.

So the water level continued to rise until it hit the second level detector connected to the 9V battery, which then sounded the alarm.

I'd also guess it started pumping when you unplugged and plugged it back in because it's designed to be able to start up again and function when power is restored after an outage long enough to have exhausted the big battery.

In short, I think you need to service or replace the big battery.
posted by jamjam at 6:08 PM on June 5, 2014 [1 favorite]

jamjam, the manual said to check the water level in the sump, not in the battery. It's a sealed battery if I recall correctly, so I don't even think I can check the battery acid levels.
posted by tckma at 12:18 PM on June 6, 2014

I should have realized it wasn't referring to the battery because individual cells of batteries can't have common pools of electrolyte (as far as I know), and therefore you'd have to look at each one individually.

But I still think the battery must be bad, a) because the pump didn't work and a bad or totally discharged battery would explain that, and b) because it seemed to charge way too fast for a good battery that was discharged but still usable:
Within the first two minutes, the charging light for the backup battery turned from red to green (indicating the backup battery is fully charged).
posted by jamjam at 2:06 PM on June 6, 2014

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