BoilerFaultCodesWorcester Bosch 1017 W Fault Code
Also written as 1017W — same fault.
The Worcester Bosch 1017 W fault code means: your boiler has stopped working because the water pressure is too low and needs to be topped up.. It appears on 10 Worcester Bosch models in our database.
Technical description: Water pressure too low – the water needs topping up and the vent system or pressure sensor may need replacing
What causes the Worcester Bosch 1017 W fault?
This fault occurs when the system loses too much water, preventing the boiler from circulating heat safely. The most common reasons are a slow leak from a radiator valve or the natural loss of pressure that happens after you bleed your radiators. If the pressure looks normal on the gauge but the code persists, the internal sensor that reads the water level may be blocked or broken.
This fault is frequently seen in autumn when homeowners turn their heating back on for the first time, as the change in temperature can highlight small leaks or air pockets in the system.
DIY fix possible
Locate the integrated filling link (blue levers) or the external filling loop underneath the boilerSlowly open the valves until you hear water moving and watch the digital display or pressure gaugeClose the valves firmly once the pressure reaches between 1.0 and 1.5 bar
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Gas Safe Register →Worcester Bosch models that show the 1017 W fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 1017 W 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