Medium Warning
815 on Worcester Bosch Greenstar 8000 Life/Style

Your boiler is receiving incorrect temperature readings from a secondary part of your heating system, which may be preventing your home from heating up efficiently.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Low loss header temp. sensor faulty

What causes this fault?

This fault occurs when the boiler loses a reliable signal from the sensor that monitors the water temperature in your external system piping. It is usually caused by a physical failure of the sensor itself or a loose connection in the wiring that links it back to the main control board. When this happens, the boiler cannot accurately measure how much heat is needed, leading to inefficient operation or a loss of heating.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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