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Sump Pump Motor Speed Control?

06/26/2011 8:40 PM

Moved into an older house with a sump pump. It's loud and pumps a lot of water when on. Is there a common type of motor used in sump pumps, and could it be speed controlled to lower the noise and have it pump slower? I realize it would run longer, but that's OK, I just want lower noise and lower flow rate.

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#1

Re: sump pump motor speed control?

06/26/2011 8:54 PM

If it is a centrifugal pump, it should not make much noise. Any speed control you could buy would probably cost more than a new pump.

How much water do you need to pump? What pump do you have now?

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#2
In reply to #1

Re: sump pump motor speed control?

06/26/2011 9:17 PM

It's a Select Series SS905; I couldn't find any info on the web. I'm thinking now of buying a new small pump, 1/6 or 1/5 HP, about $50, since this pump is probably 15 years old, same as the house. The old pump doesn't run often, but makes quite a racket. I'm thinking a smaller pump could do the job and would just run longer. It's the sump in our basement and just collects the water around the foundation.

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#5
In reply to #2

Re: sump pump motor speed control?

06/26/2011 10:02 PM

maybe being that old, a bearing or bushing could be out or going out on it. Its not a bad idea to have an extra sump around. Remember, if you slow it down, and a large amount of rain comes where it would put a strain on your sump, it may be a bad idea to cutting the capacity.

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#3

Re: Sump Pump Motor Speed Control?

06/26/2011 9:29 PM

i guess it is a directly coupled sump pump to its motor? i should not make noise, better have it check by a technician, i think it is more of alignment/bearing/coupling problem either on the pump or motor.

To lower flow rate, you can install by-pass line with a throttled valve at the discharge back to suction/source. Compare investment cost vs. installing speed controller.

good luck!

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#4

Re: Sump Pump Motor Speed Control?

06/26/2011 9:31 PM

Your approach with a new pump is almost surely the way to go.

When slowing a centrifugal pump, the flow rate decreases linearly with the speed, such as half speed = half flow. But the pressure (head) produced decreases as the square of the speed, such as half speed = 1/4 head; which might not pump the discharge high enough. Something like 80% speed might work, but it wouldn't help much with the noise.

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#6

Re: Sump Pump Motor Speed Control?

06/27/2011 1:15 AM

New pump same size for those heavy rain events. If new pump is still to noise and you have the room build a sound enclosure over the sump pit. Use something like fiber insulating board. You could always double layer it.

My 2 cents.

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#7

Re: Sump Pump Motor Speed Control?

06/27/2011 8:41 AM

Consider putting it on a timeswitch so that it only pumps while no occupant is asleep.

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#8

Re: Sump Pump Motor Speed Control?

06/27/2011 9:06 AM

I think I will add a second pump, a small one to handle the routine pumping, and leave the old big one in place for backup. And if the noise is still objectionable, I'll add some soundproofing. A timer wouldn't work since the water collects 24x7. Thanks for all the good ideas.

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#9

Re: Sump Pump Motor Speed Control?

06/27/2011 10:28 PM

Is the noise radiating from the pump, or being conducted through the piping? Maybe try isolating the pump from the plumbing with a length of flexible hose.

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#10

Re: Sump Pump Motor Speed Control?

06/27/2011 10:32 PM

I had the same problem with a noisy sump pump. The problem wasn't really the pump but the way the discharge piping was supported in the house. The plumber ran the pipes up and along a joist and secured it with clips. The solution was to run the pipe along the concrete floor and when it was near the outside wall outside through an isolating foam packing between the pipe and the wall. It's a lot quieter now.

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#11

Re: Sump Pump Motor Speed Control?

06/27/2011 10:51 PM

See McMaster Carr at http://www.mcmaster.com/#

and search for part number 42945K21 and its catalog page for other similar pumps.

These pumps are not only efficient (slightly slower) but almost silent.

Norm

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#12

Re: Sump Pump Motor Speed Control?

06/27/2011 10:57 PM

Be sure to dampen motor vibrations to the discharge pipe by using an in line check valve connected with fernco type fittings and leaving a gap between PVC pipe and check valve (overlapped by the fernco fittings).

Norm

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#13

Re: Sump Pump Motor Speed Control?

06/28/2011 12:40 AM

Simply reducing your pump speed may result in a flood......

You could use a variable speed control dependent on the level of water in the sump - ie if the water level is low the pump runs slowly, as the water rises it speeds up in increments.

One rider to this suggestion - there will be a minimum speed at which the pump will move any water because of the head it is pumping against - you can't pump slower than that, and at that speed the pump may still be noisy.

A new quieter quality pump may be the cheapest option.

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#14

Re: Sump Pump Motor Speed Control?

06/28/2011 1:03 AM

You can also dampen the motor vibration to the pit floor by placing an "old car floor mat" for example under the pump.

Norm

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#15
In reply to #14

Re: Sump Pump Motor Speed Control?

06/28/2011 2:55 AM

Had heard of that but forgotten. GA Cheap idea. Or any other rubber mats that are similar.

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#16

Re: Sump Pump Motor Speed Control?

06/28/2011 4:18 AM

Get A submersible pump, the water acts as a sound barrier & they come in all sizes,you can get one with a float built in, or one that floats in the water.

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#17

Re: Sump Pump Motor Speed Control?

06/28/2011 4:53 AM

For the pump , there is practically nothing you can do about that will not cost you a fortune. If you most reduce the noise you have to bring out the sumo pump (money), uncouple the pump end, dismantle the pump and change the worn off metal impellers to a new one or more precisely change to plastic impellers. You can also decide to change only the up risers with plastic pipes, since metal pipes used as up risers transmit disturbing noise from the pump metal impellers (little money). For the speed and volume of water, you need a VFD. The value may be enough to purchase a pump that will satisfy your demand with enough change in your pocket. So, my advice is; change the upriser pipes if they are metal pipes to plastic pipes to considerably reduce the noise only. The water volume remains the same. If above solution did not meet your requirement, buying a smaller pump with plastic impellers is recommended. Take Care.

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