Sump Pump Alternator for 2 pumps in a deep well?

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New Member
Jan 23, 2020
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I’m looking for some advice on my sump pump situation.

About 6 months ago, my basement flooded after my sump pump failed during a heavy rain. The plumber I hired installed 2 Zoeller 50 series sump pumps into my sump pump well. The well is a little unique – it is very deep (6 feet or so) and narrow. There are 2 parts of my basement – a finished area (constructed about 20 years ago) and an unfinished area (from 100+ years ago). The finished area is about 3 feet lower than the unfinished area, but the sump pump well is in the unfinished area. My best guess is that when constructing the finished basement addition for the house, they deepened the sump pump well. With these constraints, the plumber I hired after the flood told me that the well would not fit a pump with a battery back-up, so he installed the 2 pumps instead. (We have a whole house generator, so the pumps should keep working even if we lose power). As best I can tell, both pumps are sitting on the bottom of the well at the same level. It is unclear to me if there is any rhyme or reason to how the pumps turn off, if 1 is getting all the work, etc. My concern is that one of the pumps will fail, I will not know about it/replace it, and then the second will fail at a later time and I’ll end up with another flooded basement.

In trying to address this issue, it seems like a Zoeller SmartPak Plus Residential Alternator (https://www.zoellerpumps.com/en-us/products/alarms/z-control-enabled/smartpak-plus) would solve my problem. Using this system, it seems like the alternator would switch between the two pumps (extending their lives and making sure they are both working) and notify me if either stops working.

Here are my questions:

1.) Does this sound right? If not, what am I missing?

2.) Does anyone have experience with the Zoeller SmartPak Plus Residential Alternator? Is it easy to install?

3.) Will I be able to install this even though my well is so deep or will I run into problems getting the cords where they need to be?

Happy to provide any other information that would make it easier to answer my questions. I appreciate the help!


Staff member
Supporting Member
Jan 20, 2018
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Boston, Massachusetts
thats normally how a 2 pump system would work i have heard it called a lead/lag switch.....your right so they alternate use,have you tried contacting zoeller???? even with that switch....if its that critical yo should manually cycle the pumps on some sort of time period . you will know what they sound like when running/stopping,then you will
hear any noises that aren't normal...


Well-Known Member
Aug 19, 2017
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North Reading, Mass.
First and foremost you must find out exactly what you have set up before trying to add or change something.

There are a few different scenarios you could have with those 2 pumps.

As @Geofd mentioned, "Lead/Lag" is one form of control. It can simply be arranged to alternate which of the 2 pumps start first. In a traditional lead-lag system, the lead pump runs until the demand on the system is too great for the pump to meet, at which point the lag pump(s) initiates until demand is met.