BoilerFaultCodesWorcester Bosch 59202 Fault Code
The Worcester Bosch 59202 fault code means: your solar heating system is not circulating fluid quickly enough between the roof panels and your boiler setup.. It appears on 1 Worcester Bosch model in our database.
Technical description: Mass flow rate in solar system for collector group 1 is too low.
What causes the Worcester Bosch 59202 fault?
This fault occurs when the solar heating fluid is not moving through your system fast enough to transfer heat effectively. The most common reasons are an aging circulation pump that is losing power or solar fluid that has degraded and thickened over time, causing a blockage. It can also be triggered if air bubbles are trapped in the pipework, preventing a smooth flow between your roof panels and the cylinder.
This code is most frequently seen during the summer months when the solar thermal system is under the highest thermal stress and working at maximum capacity.
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 59202 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 59202 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