Error FD

Safety first

1) If you smell gas or notice burning/plastics or smoke, switch off gas at the meter if you can do so safely, turn off mains electricity to the property, leave the building and call the emergency services or the National Gas Emergency Service immediately. Do not re-enter until it is declared safe.

2) Otherwise, take normal electrical safety precautions: avoid working in wet conditions, do not open the boiler cover or touch internal components, do not attempt internal electrical repairs unless you are qualified.

Initial checks a homeowner can do

1) Check if there is a general power cut in your area or other appliances/power sockets are dead. If there was a recent power cut, wait for power to stabilise then try a reset.

2) Check the consumer unit (fuse box) for tripped breakers/RCDs and reset them if safe to do so. Check any local switched fused spur or isolation switch that supplies the boiler and ensure it is ON.

3) Check the boiler’s plug and fused spur wiring for visible damage and that the plug is fully inserted. If the boiler is hardwired, visually inspect the external supply cable for damage; do not touch exposed conductors.

Safe reset procedure (one attempt)

1) Locate the reset button on the Worcester Bosch CDi Classic boiler (consult the manual if unsure).

2) Press and hold the reset button for approximately 3 seconds, then release (manufacturer guidance often recommends a short press-and-hold).

3) Allow the boiler to complete its restart sequence — give it a few minutes to fire up and restore heating/hot water. Watch the display: if FD clears and the boiler runs normally, monitor for any recurrence.

4) Do not press reset repeatedly in quick succession; one deliberate reset is fine but repeated resets can mask an underlying fault and may damage electronics.

If FD returns or cannot be cleared

1) Note exactly when the fault occurs (after power cuts, while running, intermittently) and any related observations (noise, smells, visible damage). This information is helpful to an engineer.

2) Check for a loose fused spur switch or poor connection at the external isolation — if you are not competent with electrical work, do not attempt to open or re-terminate wiring; call a qualified electrician.

3) If the FD code keeps reappearing, or if any wiring, the fused spur, or the boiler’s power supply looks suspect, stop trying to reset and call a Gas Safe registered engineer. Persistent FD faults often require an engineer to test the mains supply, the boiler’s internal wiring and circuit board, and replace any faulty parts.

When to call a professional

1) Call a Gas Safe registered engineer if FD persists after one proper reset and basic external checks, if you find damaged wiring, if the boiler will not restart, or if other electrical problems are present in the property.

2) For any internal electrical work, circuit board faults, or component replacement, only a qualified engineer should proceed.

3) If in doubt, isolate the boiler using its external isolation switch and arrange a call-out — it’s safer to leave the boiler off than to repeatedly force a reset.

Useful information to provide to the engineer

1) The make and model (Worcester Bosch CDi Classic Regular), the FD error, when it started, whether there was a recent power cut, and any inspections you performed (consumer unit, fused spur, visible cable damage).

2) How often the fault has recurred and any other symptoms (loss of heating, strange noises, smells).

Summary

1) FD is commonly low-severity and often cleared with a single reset, but repeated or persistent FD usually indicates an electrical issue needing a Gas Safe engineer.

2) Homeowners can perform external power checks and one reset attempt, but must not open the boiler or attempt internal electrical repairs. If the fault returns or you find signs of electrical damage, call a professional.