Safety first: Isolate electrical power before removing covers or touching any sensors.

The flow temperature sensor measures the outgoing water temperature from the heater or coil.

Step 1 – Locate Flow Sensor:
- Identify the sensor on the flow outlet pipe from the Nibe water heater or on the primary circuit.
Step 2 – Check Attachment:
- Ensure the sensor is tightly clamped to the pipe or fully inserted into its pocket.
- Reapply thermal paste if recommended by Nibe and re-insulate the sensor area.
Step 3 – Wiring and Resistance:
- Inspect the cable for damage and reseat the connector at the control board.
- Measure resistance and compare with Nibe’s NTC chart if a multimeter is available.
Step 4 – Reset Alarm:
- Restore power and clear the A06 alarm.
- Monitor the flow temperature reading during operation.

Replace the sensor if readings are unstable or the alarm recurs.

The display shows A06; the water heater indicates a flow temperature sensor fault and may limit its output.

Possible Causes