Worcester Bosch 213 / D4 Fault Code
Also written as 213D4 — same fault.
The Worcester Bosch 213 / D4 fault code means: your boiler has detected that the water leaving it is much hotter than the water returning, suggesting a blockage or a problem with how water is circulating around your heating system.. It appears on 1 Worcester Bosch model in our database.
Technical description: Temperature difference between supply and return exceeding limit
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 213 / D4 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 213 / D4 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