My electric bill is going to go crazy bc my sump pump won't stop running!

April 6, 2010 5:40 PM

Our sump pump runs constantly, but only at night. Why?

Our basement has a new sump pump (less than six months old). Has a battery back up. Stainless steel sump.

The pump cycles constantly starting at about dusk, and keeps going (at least until we fall asleep). There's very little water in the sump. No more than there is during the day. During the day it doesn't run.

The plumber who installed it is coming, but he's coming during the day, and I'm afraid he's going to think I'm nuts. Can anyone think of a reason why the time of day matters?

posted by dpx.mfx to home & garden (5 answers total)

Does the pump get power during the day? Is it on some sort of timer? Do you have sprinklers that have come on before the pump runs? (ie automatic sprinklers set to run at 7pm or something?) Do you have a leak in your piping so when you do your dishes / run the dishwasher the sump fills up? Does the sump line have a check valve in it, to prevent water flowing back into the sump? Or conversly, is the sump big enough that when the outflow pipe drains back down into the sump after the pump shuts off, the level is low enough not to set your pump off again?
posted by defcom1 at 5:53 PM on April 6, 2010

There shouldn't be water in there most times unless it is raining etc. You may have some larger drainage issues to deal with.
posted by caddis at 6:09 PM on April 6, 2010

Observe the water level in the sump shortly before the time it normally starts cycling. Then observe it a couple of times once the cycling has started, before and after the pump runs. Was the water level high enough to run the pump the first time? Or did it only rise to that level after sun-down? That would tell you whether you're looking for a water leak in the evening or power that switches on in the evening.
posted by TruncatedTiller at 4:53 AM on April 7, 2010

defcon -- it gets power, it isn't on a timer (that I know of -- it does sometimes run during the day, but now that I think about it, the cycling almost always starts exactly the same time at night), no sprinklers (but maybe it's our neighbor's sprinklers! I wonder if they've started using them already?), no leak (that we know of, but the timing isn't related to running water anywhere IN the house. I don't think. Hmm. Maybe the washing machine now that I think about it.)

There is a check valve (that was new with the new sump pump). It's supposed to keep the thing from making a horrible clunking noise that the old one made?

Caddis, we're the low part of the neighborhood, and we have an underground spring, so there is almost always some water in it.

thanks guys. Lots to think about. I'll let you know what the plumber says tonight!
posted by dpx.mfx at 11:20 AM on April 7, 2010

At least the plumber didn't think I was crazy; he just replaced the pump. Something to do with the float mechanism being faulty.
posted by dpx.mfx at 5:00 AM on April 8, 2010