E06
ACV DHW Temperature Sensor Fault (NTC Open/Short)

Display shows E06, unit may run briefly then shut down, domestic hot water temperature unstable

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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 ACV DHW NTC sensor, Damaged sensor cable, Corroded connector at sensor pocket, Fault on control board sensor input

How to Fix / Troubleshooting

Safety: Turn off power before working on electrical connections.

  • 1. Identify DHW sensor: On ACV water heaters, the DHW NTC is typically inserted into a dry pocket on the tank or on the DHW outlet pipe.
  • 2. Visual inspection: Check for moisture, corrosion, or scale around the sensor pocket. Ensure the cable is intact and not pinched by the casing.
  • 3. Check connections: Reseat the connector at both the sensor and the control board. Look for green corrosion or burnt pins.
  • 4. Resistance test: With power off, disconnect the sensor and measure resistance. Compare with ACV's NTC chart. Replace the sensor if readings are clearly wrong or intermittent when the cable is flexed.
  • 5. Refit and test: Install the new ACV DHW NTC sensor, ensuring it is fully inserted into the pocket. Restore power and check if E06 clears and DHW temperature stabilizes.

If E06 persists with a known-good sensor, the main PCB may require replacement by an ACV-authorized technician.

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Repair Difficulty

Medium 3/5

Required Part

DHW Temperature Sensor (NTC)
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