Say Goodbye to Mechanical float switches, and Hello to Digital Level Control

Ion Digital Level Control

Romeoville, Ill.,-based Metropolitan Industriesbelieves that intelligent microprocessor technology represents a sea change over mechanical switch operation in sump pumps.   

Under development for several years, Metropolitan’s patent-pendingIon Digital Level Controllereliminates moving parts, which are the detriment of most mechanical switches, and replaces it with solid-state sensing technology, which testing has shown to last 1.5 million cycles,  approximately triple the life of a mechanical switch.   

“The problem was never the pump, because they are generally built to last. The problem has always been the switch responsible for the critical task of turning the pump on and off,” says John Kochan, Jr., Metropolitan Industries’ President, who developed the idea for the new product by utilizing solid state components and applying them to switch technology.   

While mechanical switches are useful and function properly over a period of time, they are always subject to failure. “Mechanical switches use moving parts and wear and tear in a sump pit environment will always break those components down over time,” Kochan, Jr. says.   

Switch failures translate into non-running pumps, which can result in flooded commercial, industrial and residential locations.   

With the demand for reliable switches evident with recent recalls put forth by some of the largest pump manufacturers during the last decade, Metropolitan began work over a period of five years to develop a product that can outperform mechanical switches in longevity and dependability. 

How It Works

The ION Digital Level Controller is a technologically advanced device that senses water level/pressure through the use of a proprietary sensor and microprocessor-driven digital control. The microprocessor within the digital float sensor samples analog data from the proprietary sensor, which electro-mechanically converts the water pressure to an electrical resistance. Because water pressure is directly proportional to the water height, the electrical resistance of the proprietary sensor is also proportional to the water height. The resistance of the proprietary sensor is measured by means of a resistive bridge network before passing into the microprocessor’s analog to digital converter.   

Traditionally, sump and sewage pumps have been started by means of a mechanical switch. The mechanical switch design often uses a set of electrical contacts that close under a given water height scenario, thereby activating the sump pump. Due to the alternating nature of the electrical voltage source from the utility, large voltage differentials could possibly be present across the mechanical switch contacts prior to turning on a pump. 

When a pump is suddenly turned on under these conditions, large transient current surges could be expected as the motor begins to rotate. These transient surges often cause heating of the electrical contacts which, over time, effectively reduce the lifetime of the switch. This condition is further amplified when a mechanical switch attempts to open and turn off the pump.   

When a mechanical switch suddenly opens an inductive motor load, the time rate of change of the current flow can be very large. This value, multiplied by the motor’s internal inductance, induces a large voltage transient across the mechanical switch contacts. This transient often causes arcing of the contacts which over time, can cause the switch to wear and ultimately fail. It is well known in the sump pump industry that the cause of most pumping failures occurs when the pump switch fails.   

The embodiments of the ION Switch effectively eliminate the problem of switching transients and contact arcing by incorporating both a solid-state switching device in parallel with an electrical relay. When a pump is called for, the turn-on cycle begins by enabling the solid-state device. The solid-state device in

Metropolitan’s design is to switch on a load under low voltage conditions. By engaging the electrical relay from a low-voltage potential, both radiated and conducted electrical noise have been dramatically reduced.   

The Ion Digital Level Control is universal and can be used in almost any pumping application dependent on level control as well as effluent sump and sewage. To customize operation, the Ion Digital Level Control has standard differential heights of 6 inches for standard sump applications and 10 inches for sewage applications, and is inverter rated for use with most battery back-up systems. The Ion can be programmed for custom applications as well.   

“We feel the Ion Digital Level Controller will transform the pump industry much the way battery back-up systems did in the 1980s, because we figured the way to eliminate the moving parts associated  with most switch failures,” Kochan, Jr. says.   

“As wholesalers and plumbers realize there is a product available that can eliminate the problems associated with mechanical switches, it will only be a matter of time until mechanical switches are replaced entirely.”     

For further information about the Ion Digital Level Controller