Your boiler has detected a problem with the temperature sensor that monitors the water returning from your radiators, causing it to stop heating for safety.

Return–NTC: – NTC broken – NTC cable broken – Defective connection at NTC – Defective connection at electronics | Return–NTC cable defective/broken NTC faulty

What causes this fault?

This fault occurs when the piece of equipment responsible for measuring the temperature of the water returning to the boiler stops sending a clear signal. This is usually caused by the internal sensor failing due to age or a loose electrical connection in the wiring that links the sensor to the boiler's main control board.