BoilerFaultCodesWorcester Bosch 59201 Fault Code
The Worcester Bosch 59201 fault code means: your solar heating system is circulating liquid too quickly, which usually means a sensor is misreading or the pump speed needs adjusting.. It appears on 1 Worcester Bosch model in our database.
Technical description: Mass flow rate in solar system for collector group 1 is too high.
What causes the Worcester Bosch 59201 fault?
This fault occurs when the fluid in your solar heating circuit is moving faster than the system's safety limits allow. It is usually caused by a malfunctioning flow sensor providing incorrect readings or a solar pump that has been set to an unnecessarily high speed. In some cases, a glitch in the solar control module can also cause the system to mismanage the circulation rate.
This issue is most frequently noticed during the summer months when high solar gain triggers the pump to run at maximum capacity more often.
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 59201 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 59201 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