Among the most common methods for pump control in lift stations is the use of multiple cable suspended float switches. While this method may appear to be the least expensive, it also involves the most risk and hassle.
One of the biggest unforeseen costs with multiple individual floats is maintenance. Many lift station techs plan on replacing one float switch per year due to the lack of quality of these less expensive units. In addition, having several cable suspended float switches in the same well will often result in tangled floats.
If tangled, the float switches are no longer reliable. They may not activate at the proper level, or worse - fail to activate at all. While you may be able offset this issue by securing the floats to the side of the tank, this strategy is not always an option since wells and tanks vary in structure.
With the expectation of common float switch failure, and the possibility of entanglement, the risk and hassle of this approach is very high. The cost associated with a lift station spill goes without saying. So how can reduce the cost of ownership and increase the reliability and longevity of your float switches?
Multi-Switch Point Floats
If you want to reduce cost of ownership, but still use something budget friendly, then you should consider purchasing a multi-switch point float. The only one on the market is our KA series float switch. These sensors have multiple switches within one float housing that switch at different angles. A control weight is fixed at a point along the cable making the float tilt as the liquid rises. The increasing tilt of the float activates the switches at different levels. For more information on how these switches work, take a look at our KA series cable suspended float switch.
So with a KA float switch you keep cost down, and still get the convenience of an easy install as with any other cable suspended float switch. In addition, KA switches are built to a much higher standard. It is common for these to last 8-10 years in the field. In the end, you will have no more tangled cables and you will spend less of your valuable time maintaining and replacing floats.
Stem Float Switches
The second alternative to using multiple cable suspended float switches is to use a stem float switch instead. Since all of the floats will be fixed to the stem, you won’t need to worry about tangled cables. In addition, any stem float switch worth its salt is more rugged. For example, our FLX series is built for harsh applications, made of 316L stainless steel, and carries CSA hazardous location certifications. You can expect an FLX to last longer than a standard cable suspended float switch.
Don't Use Float Switches
Of course another option is to use a better technology. Ultrasonic sensors, like our LPU-2428, are great for continuous level measurement and better pump control options. Submersible pressure transducers, like our PT-500, are another great option for lift stations with foam, unusual turbidity, and still offer a continuous measurement for advanced pump control.