E16
Crystal Quest Water temperature sensor fault

Display shows E16 and unit reports temperature error (on models with temperature monitoring).

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Failed temperature probe in Crystal Quest control head, Sensor wiring damage, Water temperature outside specified range, Control board analog input failure

How to Fix / Troubleshooting

Safety first: Unplug the unit before accessing sensors.

  • Check water temperature: Measure inlet water temperature. Ensure it is within Crystal Quest's allowed range (typically 40–100°F / 5–38°C). If hot water is feeding the softener, correct the plumbing.
  • Inspect sensor: Locate the temperature sensor (often in the inlet port or valve body). Check for secure mounting and intact wiring.
  • Replace sensor: If wiring is good and water temperature is normal, replace the Crystal Quest temperature sensor.
  • Board check: If E16 persists with a new sensor, the main control board may be defective and require replacement.
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Repair Difficulty

Medium 3/5

Required Part

Crystal Quest temperature sensor
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