BoilerFaultCodesWorcester Bosch Fd Fault Code
Also written as FD — same fault.
The Worcester Bosch Fd fault code means: your boiler is showing this code simply because the reset button was held down for too long or pressed by mistake, which has confused the internal software.. It appears on 26 Worcester Bosch models in our database.
Technical description: Mains power error - electrical power interruption
What causes the Worcester Bosch Fd fault?
This fault occurs when the boiler's control board detects that the reset button has been compressed for a prolonged period, typically more than 15 seconds. It usually happens if the button is pressed too hard, held down in an attempt to clear another error, or if the button has physically stuck inside the control panel. The boiler enters this state as a safety precaution because it cannot distinguish between a genuine reset attempt and a hardware malfunction.
DIY fix possible
Press the reset button firmly once and release it immediately.Wait up to 30 seconds for the boiler to clear the code and restart.If the code persists, turn the power to the boiler off at the wall switch, wait one minute, and turn it back on.
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Worcester Bosch models that show the Fd fault code
Click a model for the full fault code list and model-specific repair notes.
- 537i
- CDi Classic
- CDi Classic Regular
- CDi Highflow
- Greenstar 12i System Repair: £0-80
- Greenstar 25 HE Combi
- Greenstar 25HE
- Greenstar 28CDi
- Greenstar 30CDi Classic System ErP
- Greenstar 30HE
- Greenstar 30i
- Greenstar CDi Compact
- Greenstar i
- Greenstar R29 40 HE
- Greenstar Ri
- Greenstar Si Combi / i System
- Greenstar System
- Greenstar ZWB7
- Hideaway 90
- Highflow 440 CDi
- Highflow 550 CDi
- R30 HE Plus
- Ri 25 HE
- Worcester 25/30 HE
- ZB 7 27 HE
- ZWB 7-25
Source
Worcester Bosch Fd 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 537i manual (PDF)
- Worcester Bosch CDi Classic manual (PDF)
- Worcester Bosch CDi Classic Regular manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026