Gear Test: Johnson UltimaSwitch - Soundings Online

Gear Test: Johnson UltimaSwitch

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The UltimaSwitch bilge pump switch by Johnson Pump differs from the more common float switch used to control your vessel’s bilge pump by the fact that it contains no moving parts that can jam, wear and otherwise degrade in a relatively short time.

The UltimaSwitch bilge pump switch by Johnson Pump differs from the more common float switch used to control your vessel’s bilge pump by the fact that it contains no moving parts that can jam, wear and otherwise degrade in a relatively short time.

Its sonically welded ABS thermoplastic housing relies on Mirus field detector cells and solid-state electronics to control pump operation.

 The field detector cells produce microelectrical fields that, when interrupted by fluid, provide a signal to the solid-state electronics controlling pump function. The UltimaSwitch contains two detector cells: one that activates the pump when the water level rises to 2 inches from the base of the switch, and one that turns off the pump when the water level recedes a half-inch from the switch base. The function of the Ultima-Switch isn’t affected by the normal mix of contaminants found in bilge water, according to Michael Collins, engineering manager for Johnson Pumps.

 

The switch includes 30 inches of tinned stranded wire and Johnson’s “T slot” mounting ears. There are additional mounting ears provided that enable the switch to be installed with bilge pumps from other manufacturers, or used to activate a high-water alarm. The UltimaSwitch can be used on both 12V DC and 24V DC bilge pumps without adjustments, but cannot be used at any other voltages. The maximum current draw from the pump shouldn’t exceed 20 amps. The UltimaSwitch should be compatible with existing bilge pump control switches and panels, simplifying retrofit.

To test the switch and compare it with two float switches I commonly see installed in boats, I set up a simple test tank. I installed the UltimaSwitch on a Johnson 1,600-gph bilge pump using its “T” slot mounting system, and screwed the completed assembly to 3/8-inch Starboard along with Rule-A-Matic Plus and Sure Bail mechanical-type float switches. I wired the UltimaSwitch to activate the bilge pump, while the other switches were connected to activate 12-volt lights that would simulate the pumps being turned on.

To accurately determine the water level required for activation, I placed the test panel in a suitable container that allowed me to add water for the pump “on” function, and gave the bilge pump the ability to discharge water and cycle the switches to “off.”

All three switches routinely activated their devices at the 2-inch water level, although the UltimaSwitch was more consistent. The switch circuitry incorporates a three-second delay, which worked effectively to eliminate premature pump activation caused by turbulence in the water. The small amount of water movement created by the garden hose filling the container was enough to activate the mechanical float switches ahead of the UltimaSwitch. As the bilge pump discharged water from the tank, the two mechanical float switches shut off their circuits at or near a half-inch of standing water, while the UltimaSwitch remained on for an additional second or two. The additional run time may well assist with discharging the remaining water from the hose and eliminate the common problem of water draining back into the bilge from elevated discharge lines.

Holding two fingers over the raised circular areas on the side of the switch for about 10 seconds can serve to test the unit. If the switch and pump wiring is correct the pump should activate. If you remove a finger from the top circle, the pump should remain on, while removal of both fingers signals the pump to shut off following a short delay.

The UltimaSwitch is based on proven field-effect switching and sensing technology used in numerous industries and applications. The construction and materials in this switch appear to be capable of maintaining their integrity and are covered by a three-year limited warranty. The physical size of the Ultima-Switch (about 2-1/2 inches tall, 3-1/2 inches wide, 1-1/8 inches thick), simple installation and inherent reliability of solid state components should make it a reliable performer.

Manufacturer’s suggested retail price is $47.25, but it is available from major retailers for around $35. For more information contact Johnson Pumps at (847) 671-7867, or visit www.johnsonpump.com.