Fd Low

Worcester 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 39 Worcester Bosch models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

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.

Typical repair cost £0-80 (including labour)

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.

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.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026