Choosing the Right Kari Float Switch

underwater view of new kari float switchKari float switches are the most innovative cable suspended float switches on the market, and they were invented back in 1965! And that’s more than just a sales pitch. The floats can contain up to four mechanical switches with over 20 different control and alarm configurations.

So with all these switch combinations and control configurations, the only hard part about buying one is the selection process. Hence, this helpful article all about choosing the right Kari to make all your wildest dreams come true – at least the float switch related ones.

Fill vs Empty Control

The first question that needs to be answered is do you need to control the filling or emptying of a vessel. This splits the field of options in half. It’s the difference between a normally open (form A, NO) and a normally closed (form B, NC) switch.

Due to a few configurations with alarms, you can get a float switch with both NO and NC closures. However, the main function of the float switch will determine its form.

Number Of Switch Points

The second item on your need-to-know list is how many switch points you need to achieve the control goal. You can order a Kari float switch with one, two, three, or four switch closures.

The number of switches in a float also directly affects the complexity and number of the configurations.


A few of the models have built-in hysteresis, which prevents the on-off controls from chattering (quickly changing states due to waves or turbulence). This feature is absolutely critical for backup pump control because the float can stand alone as a backup sensor without the need for controllers. The float only needs to be wired correctly to an appropriate contactor.

If you need hysteresis (it’s not a part of your control system, or you don’t want it to be), then you’ll need to pay attention to the models that have it built in.

Isolated Alarms

You might be required or want to have isolated switch points. This means there is at least one switch point that has an isolated circuit. You can wire it to a lower voltage alarm circuit, and it provides an added layer of safety in case something happens on the main control circuit.

There are six Kari models that have isolated switch points. If you need an isolated switch, it narrows down the playing field substantially.

Use The Diagrams

To make this as easy as possible, we have created (and recently updated and improved) diagrams that explain how the configurations work and what they will do for you. The diagrams are featured in the datasheet, but we have made a downloadable pdf for your immediate viewing pleasure.

selection guide for kari float switchesThis guide illustrates the switching action of the different Kari models. There are 25 different configurations, each with a specific control function in mind.

To get a better look, we recommend downloading the pdf. Let us know if you need help reading the diagrams.

Tell Us About Your Application

The most reliable way to choose the right Kari float switch is to get ahold of us and tell us about your application. We’ll help you weigh your options so you get the best instrument for the job.

We're available via phone, email, or live chat, and are ready to walk you through the process. Let us know if we can help!

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