BoilerFaultCodesTechnical description
Return sensor open circuit
What causes this fault?
This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the water returning from your radiators. This is usually caused by the internal sensor failing electrically or a connection point within the wiring becoming loose or damaged over time. Because the boiler can no longer safely track how much heat is in the system, it shuts down as a safety precaution.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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