BoilerFaultCodesWorcester Bosch E5 Fault Code
The Worcester Bosch E5 fault code means: your boiler has encountered an internal electronic communication error that is preventing it from running safely.. It appears on 11 Worcester Bosch models in our database.
Technical description: Flow temperature too high. Primary sensor overheated.
What causes the Worcester Bosch E5 fault?
This fault occurs when the boiler's internal computer brain fails to communicate properly with the other sensors and components inside the unit. It is usually caused by a physical failure of the main circuit board or a loose connection in the internal wiring harness that prevents data from traveling through the system. Because the boiler cannot verify that it is operating safely, it stops running as a protective measure.
DIY fix possible
Press the 'Reset' button on the control panel once.Wait up to 15 minutes for the boiler to restart.If the code persists, do not attempt further repairs and contact a Gas Safe engineer.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like E5: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Worcester Bosch models that show the E5 fault code
Click a model for the full fault code list and model-specific repair notes.
- 533 Compact
- 535 Compact
- Greenstar 25 Si Compact Repair: £150-300
- Greenstar 25Si Compact ErP Repair: £150-300
- Greenstar 27i System Compact ErP Repair: £150-300
- Greenstar 28CDi Compact ErP Repair: £150-300
- Greenstar 30 Si Compact Repair: £150-300
- Greenstar 30i System Compact ErP Repair: £150-300
- Greenstar 30Si Compact ErP Repair: £150-300
- Greenstar CDi Compact Repair: £150-300
- Greenstar Heatslave II Repair: £250-550
Source
Worcester Bosch E5 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
- Worcester Bosch 535 Compact manual (PDF)
- Worcester Bosch Greenstar 30 Si Compact manual (PDF)
- Worcester Bosch Greenstar 30Si Compact ErP manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026