Help! Sump Discharge issues

14 Jul 2008
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United Kingdom
I hope someone can help.

My sump pump currently drains into my laundry tub, and has worked fine for the past 5 years. However I recently replaced the 1/3hp unit with a 2/3hp unit (after the 1/3 failed), and now the pump is too powerful. In retrospect I should have stuck with 1/3hp, but it's too late to return the 2/3 one (and too expensive to simply not use it).

The issue is that the laundry tub is unable to drain fast enough to accommodate the new pump, and it will overflow pretty much each time the pump comes on.

Having the pump discharge into the backyard is not an option because the entire span of the back is a flagstone patio and main walkway (and we don't want to be sprayed with water). The pipe cannot drain to the front of the house because the entire span is a large solid concrete patio which is about 3 feet high (plus I wouldn't want the front yard to be a swimming pool). The left side of the house is too far (approx. 40 feet from the sump pit, uphill). The only other option is to drain onto the driveway (which is actually the closest to the sump pit), but I'm concerned with freezing the discharge pipe here in Canada (especially since the pump has a backfill valve, so the pipe would stay full of water most of the time); not to mention the icy driveway it would create.

Any suggestions?
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in the UK it is not permitted to put groundwater into a public sewer.

I think you are going to need to dig a soakaway a suitable distance drom your home and dig a trench for a pipe to it.

what happens to the rainwater from your roof?
What type of pump motor is it ? Some types are easy to regulate the speed with a triac drive (phase/burst mode controllers).

Perhaps you could just throttle down the outlet or have a bypass back into the sump reducing the output to the "laundry tub" whatever that is :) .

What type of impeller does it have ? How about machining down the diameter or reducing the height of the vanes (if it's not a shrouded impeller) to de-rate it.

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