Safety first: Disconnect power before opening the control head.

Locate the temperature sensor: On Aquabion models with temperature monitoring, the temperature probe is typically inserted into a well on the valve body or inlet manifold. Verify it is fully inserted and secured.
Inspect wiring: Trace the temperature sensor harness from the probe to the main control board. Ensure connectors are tight and wires are not pinched or cut.
Check sensor resistance: With the unit powered off, disconnect the sensor and measure its resistance with a multimeter. Compare the reading to the Aquabion service chart for the current water temperature. Replace the sensor if readings are out of range or open/shorted.
Control board diagnosis: If a known-good sensor still results in E06, the main control board input circuit may be defective and require replacement.

Warning: Do not run hot water through a cold-water-only Aquabion softener; excessive temperature can permanently damage internal seals and resin.

Display shows E06 and the Aquabion softener reports abnormal water temperature or shuts down.

Possible Causes