BoilerFaultCodesWorcester Bosch E44 Fault Code
The Worcester Bosch E44 fault code means: your boiler has detected that there is too much water in the system combined with high temperatures, causing it to shut down for safety.. It appears on 1 Worcester Bosch model in our database.
Technical description: High water pressure with temperatures reaching
What causes the Worcester Bosch E44 fault?
This fault occurs when the internal water pressure becomes too high while the boiler is running, often caused by a faulty filling valve that is letting too much water into the system. It can also happen if the expansion vessel, which manages pressure changes as water heats up, has failed or lost its air charge. When these two factors combine, the boiler shuts down to prevent internal components from being damaged by the excessive force.
This fault is more common during the first cold spell of autumn when the heating is turned on for the first time in months, putting sudden stress on the expansion vessel.
DIY fix possible
Check that the internal or external filling loop valves are fully closed.Bled water from a radiator bleed valve to reduce the system pressure.Monitor the pressure gauge to ensure it stays between 1.0 and 1.5 bar when cold.If pressure rises again without intervention, contact a Gas Safe engineer.
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Gas Safe Register →Worcester Bosch models that show the E44 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch E44 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