BoilerFaultCodesWorcester Bosch 1017 Fault Code
The Worcester Bosch 1017 fault code means: your boiler has stopped working because the water pressure inside the system has dropped below the minimum level required to operate safely.. It appears on 5 Worcester Bosch models in our database.
Technical description: System pressure too low
What causes the Worcester Bosch 1017 fault?
This fault occurs when the internal sensors detect that there isn't enough water circulating in your heating system to operate safely. The most common reason is a slow leak from a radiator valve or pipework, but it can also happen if you have recently bled your radiators and haven't topped the pressure back up.
This issue is more common in autumn when homeowners turn their heating back on for the first time or bleed their radiators to prepare for winter.
DIY fix possible
Locate the internal or external filling link (often blue levers or a braided hose under the boiler).Slowly open the valves until you hear water entering the system.Watch the digital display or pressure gauge until it reaches between 1.0 and 1.5 bar, then close the valves completely.
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Gas Safe Register →Worcester Bosch models that show the 1017 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 1017 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