BoilerFaultCodesWorcester Bosch CE266 Fault Code
The Worcester Bosch CE266 fault code means: your boiler has stopped working because it cannot detect any water being moved through the system by the internal pump.. It appears on 1 Worcester Bosch model in our database.
Technical description: Pump test failed
What causes the Worcester Bosch CE266 fault?
This fault occurs when the boiler's control system attempts to start the internal pump but fails to detect the expected change in water pressure or flow. The most common reason is that the pump has become seized or electrically faulty, though it can also be caused by a blockage in the heat exchanger or a failing sensor that is unable to report that water is moving correctly.
This issue often develops at the start of autumn when a pump that has been idle all summer becomes stuck due to a buildup of internal debris.
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 CE266 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch CE266 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