High Lockout
37 on Remeha Quinta 115

Your boiler has stopped working because it cannot correctly measure the temperature of the water returning from your radiators.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Return temperature sensor failed

What causes this fault?

This fault occurs when the boiler's internal computer stops receiving a reliable signal from the component that monitors water temperature coming back from your heating system. The most common reason is that the sensor has electronically failed or 'drifted' out of its safe operating range, though it can also be caused by a loose connection or damaged wiring. Because the boiler can no longer safely monitor its own temperature, it shuts down to prevent potential overheating.

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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