Boiler displays A07, heating stops, flow temperature reading abnormal

Safety: Turn off power and allow the boiler to cool before touching the flow pipe or sensor pocket.

Steps:

• Visual inspection: Locate the flow NTC sensor on the flow pipe leaving the heat exchanger. Check that it is fully inserted into its pocket and secured with its clip.
• Check connections: Ensure the sensor plug is firmly connected to the harness and there is no corrosion or moisture on the contacts.
• Compare temperatures: If the display shows extreme or fluctuating temperatures while the boiler is cold, the sensor is likely defective.
• Reset: After reseating the connector, restore power and reset the boiler.

Technician role: A professional can measure the NTC resistance at known temperatures and replace the sensor or wiring harness if out of specification.