Selecting Your Switch


Select The BestSwitch Type For Your Installation

Choosing which switch your sump pump uses can have a large impact on how long your pump will last.  It is best to choose a switch that will allow the pump to discharge as much water as possible when it runs, then be off long enough for the pump to cool completely.  Allowing the pump to cool off completely will help provide the longest possible life for your sump pump.

The first, and most important part, of choosing the switch type is your sump basin or pit size that you measured in the previous step.  It is critical that the switch be able to operate freely without the possibilty of hitting the basin wall or other obstruction in the pit which would cause it to get stuck.

Tethered Switches Vertical Switches Electronic Switches
14" minimum diameter 10" minimum diameter 10" minimum diameter
Tethered switches float upwards at an angle as water enters the basin to activate the pump. Pump turns on when bulb is nearly straight up; turns off when hanging nearly straight down. The vertical switch float moves straight up on a rod as water enters to activate the pump.   It activates a switch at the top to turn on the pump.  When the float goes to the bottom it pulls the rod down to turn off the pump. Electronic Switches usually use a combination of metal probes to "feel" the water.  When water touches the 'on' probe and the common one, the switch activates.  When water no longer touches the 'off' probe, it turns off.

Advantages:  Provides a longer run time, and a longer 'rest' time for the pump. This means the pump can cool off more completely between cycles.  Also, the amount of cord between the attachment (pivot) point and the float can be adjusted.  This is great if you have an unusually large sump pit.  You can "fine-tune" your pump's on and off points

Disadvantages:  Requires a larger sump pit so that it does not get stuck on the walls of the pit.

Advantages:  Since the float only moves straight up-and-down, this switch can operate in a very narrow sump pit.  There is a bit of adjustability to the switch's "off" point.

Disadvantages:  The narrow range of operation makes the pump run more often, and provides less "rest" time between cycles for the pump to cool off.

Advantages:  No moving parts means there is nothing that can get stuck.  This means the pump is very unlikely to fail to start or stop because of obstructions in the basin.

Disadvantages:  If your ground water contains a lot of lime, calcium, or other contaminants, it is possible for those to collect on the probes and coat them.  This could mean the probes will not "feel" the water and turn on.  You may have to clean off the electronic probes periodically.

It is important to consider sump pit size and switch type if you are considering the use of a battery backup sump pump in your pit.  You need to make sure that there is room in the pit for both switches to operate freely.

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Next:  Materials of Construction

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