BoilerFaultCodesWorcester Bosch 53125 Fault Code
The Worcester Bosch 53125 fault code means: your boiler's solar heating sensor has detected an unusually high temperature or a technical fault, causing the system to stop as a precaution.. It appears on 1 Worcester Bosch model in our database.
Technical description: Collector temperature sensor (T1) fitted on collector array inlet.
What causes the Worcester Bosch 53125 fault?
This fault occurs when the sensor on your roof's solar panels detects that the fluid has become too hot or if the sensor itself has developed an electrical failure. It is often caused by a lack of fluid circulation in the solar circuit or a degraded sensor that is sending incorrect temperature readings to the boiler.
This fault is most common during the summer months when high levels of solar radiation can lead to the solar fluid overheating if the system isn't circulating correctly.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Worcester Bosch models that show the 53125 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 53125 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026