Water is back flowing on sump pump in very old building.


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Old 11-25-15, 12:34 PM
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Water is back flowing on sump pump in very old building.

Working on some projects at a VERY old historic building.

Sump pump pit is approx. 11" in diameter by 15" deep.

There is approx 60' of 1.5" pvc pipe with many turns/verticals/horizontals etc.

Long story short, there is no way to re-pipe or re-route the piping. I repeat, no way to re-pipe.

Problem:
Water is back flowing down the pipe and I have standing water in the piping.
Pit overflows and puts water all over a basement floor.

There is no check valve currently. I am planning on adding one.

Question #1 - Can I (or should I) put more than one check valve in the system?
One near the pump, and one higher up on the piping? Or will one be sufficient?

Question #2 - Will increasing the power of the pump help get more of the water out in each discharge?

Thanks!
 
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Old 11-25-15, 12:46 PM
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1. You can, but aside from providing redundancy should the first one fail, it doesn't really help anything.

2. The pump will run until the float drops. If the current pump is powerful enough to overcome the head and pump water out until the float drops, then changing to a more powerful pump won't accomplish much. A more powerful pump would be called for if the current pump can't keep up with the amount of water flowing into the pit.

I don't understand why the pit overflows, even without a check valve. When the pump shuts off, and water starts flowing backward and refills the pit, the pump should turn back on and pump it out again. Lack of a check valve usually just causes short cycling where the pump runs very frequently because it's pumping some of the same water over and over.

Is the pump running when the pit overflows? If not, you have a problem with the float getting hung up or perhaps a bad float switch or waterlogged float.
 
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Old 11-25-15, 12:52 PM
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Well, I did a couple of test runs and the pump seems to kick on a little too late..

After it pumps, water back flows back down the pipe and into the pit..
as the pit fills, it comes up to the float and then about 5-10 seconds LATER it kicks on.

Maybe best that I just replace with a new pump and install the check valve and then see if I still have problems after that, eh?
 
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Old 11-25-15, 01:06 PM
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It does sound like your float switch is marginal. Once the float lifts it should start right up. Pumps aren't that expensive, so since you have to add the check valve, probably makes sense to replace it.

The pump instructions will tell you to drill a little hole in the drain pipe below the check valve so the pump doesn't airlock. Don't ignore that. Good luck!
 
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Old 11-25-15, 02:05 PM
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Thanks for all the input, I appreciate it.

If I drill a hole below the check valve won't water leak out of it?

Have a wonderful thanksgiving by the way!

David
 
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Old 11-25-15, 04:09 PM
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It's only a tiny hole, like 1/8" diameter. Water will squirt out it when the pump is running, so it has to be low enough to be in the pit, usually just a couple inches above the bottom of the pump. Because it's a small hole, the amount of water doesn't hurt anything. It's there so if the pit ever goes dry and all the water drains out of the pump, the air in the pump won't prevent the pump from priming itself next time it's needed.

You have a happy thanksgiving also!
 
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Old 11-25-15, 04:45 PM
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Where is the water pumped to? It should not be dumped or spilled on the ground just outside the building.

Does the sump pump empty out the pit almost completely before it stops? Usually the pump works best if it starts before the large drain pipes in the sides of the pit are more than half submerged and keeps running until the pit is almost completely empty. There are some idiosyncrasies that can sometimes happen only a few times during the year when you need to adjust the floats differently..

Any chance you can make the pit larger or dig a second pit next to it and connected to it at the bottoms (to let more water to accumulate before the pump has to start up again)?
 
 

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