Adjusting the Sensors on the EGO 500 SELS Automatic Pump

The EGO 500 SELS uses electronic water-sensing probes rather than a traditional float switch. This allows low level automatic operation in shallow sumps or tight chambers where floats may otherwise jam, or stick - whilst also not pumping as low as desired.

Three stainless probes are mounted on a vertical rail:

• 1 Brown probe – common reference
• 2 Black probe – Stop level
• 3 Blue probe – Start level

Factory Settings

From the factory, the EGO 500 SELS is typically set to:

• Turn on at ~125 mm water depth
• Turn off at ~40 mm water depth

• Water reaching the start probe turns the pump on.
• When the level falls to the stop probe, the pump turns off - with a short run-on to finish clearing water and prevent repeated on/off switching.

Adjustable Sensor

The sensor holders can be slid up or down the rail and locked in place with the fixing screws.

• Start level (blue probe) adjustable down to approx 15 mm
• Stop level (black probe) adjustable down to a few millimetres

Note: the pump runs for a short while after the water level has dropped below the off level, enabling low level pumping down to a mm. However, to help prevent it running dry, the off level should be set no lower than 3–5mm.

Probe 1 (the brown wire) is the common reference electrode. It doesn’t define a water level by itself. Instead, it provides the electrical reference that allows the control card to detect when water has reached the start or stop probes.

The SELS system detects water by sensing electrical conductivity. Water conducts electricity slightly. The control unit applies a small sensing voltage between:

• The common reference probe (brown)
• And one of the level probes (start or stop)

When water touches both probes, it completes a tiny electrical circuit. The control unit sees this and knows water is present at that level.

Considerations

It’s also important to consider the size of the chamber and the inflow rate. If the chamber is very small and the levels are set too low, the pump can drain the area quickly and cycle on and off in rapid succession. This short-cycling can lead to premature wear and failure, which would not be covered under warranty, as it results from unsuitable setup rather than a pump fault. The level settings must therefore be matched to the chamber size and expected inflow conditions.

Benefits of the EGO500SELS include:

• No external float switch to snag
• Low level pumping
• Clean operation in narrow chambers
• Fine control over start and stop levels

This is why the SELS is particularly well-suited to puddle pumping behind Flood Barriers, basement sumps, and temporary flood response setups.