Error 208

Safety precautions:

- If you smell gas, leave the property immediately, call the gas emergency number and do not operate any electrical switches or the boiler. Do not attempt to fix gas or flame-related faults yourself.

- Turn off electrical power at the fused spur or the boiler’s isolator before opening any covers or attempting internal checks. Do not open the boiler casing unless you are a qualified engineer.

- Do not tamper with gas valves, ignition components, the burner or the flue. Only a Gas Safe registered engineer should work on gas or combustion components.

Initial homeowner checks you can safely do:

1. Confirm the display shows code 208 and note any other codes or flashing indicators. 208 specifically means chimney sweep mode.

2. Check whether the boiler was recently serviced. An engineer may have deliberately left it in sweep mode after a service. If so, contact that engineer to switch it back.

3. Check the boiler control knob and any visible service or mode switches. Some models have a service switch or a specific position on the temperature dial that enables sweep mode.

4. Check the boiler pressure gauge. If pressure is very low (typically below 1 bar), top up the system following the boiler manual before further troubleshooting. Low pressure is a separate issue but can cause other faults.

Simple reset and power-cycle steps (safe first actions):

1. Try a normal reset: Many Worcester boilers have a clear reset button to press and hold for about 3 seconds. On some models you hold the temperature dial at the reset symbol or turn to a reset/light position for 3 seconds. After resetting, turn controls back to normal and wait to see if the boiler returns to normal operation.

2. If reset does not clear it, switch the boiler off at the wall isolator or fused spur, wait 30 seconds and switch it back on (power-cycle). Check the display again.

3. If you have a manual that shows how to exit chimney sweep or service mode, follow that exact procedure. Do not try hidden service menus beyond what the manual advises for homeowners.

If the boiler remains in chimney sweep mode after the above:

- Do not attempt to access internal components or the PCB. Persistent service mode could indicate a stuck service switch, a fault in the control board, an incorrect configuration, or a communication/code plug issue that requires diagnostic equipment.

- Note any other error codes or unusual behaviour (no flame, repeated lockouts, loud noises, loss of heating/hot water) and record them for the engineer.

When to call a professional:

- If reset and power-cycle do not return the boiler to normal operation.

- If other fault codes appear alongside 208 or if the boiler will not produce heating or hot water as expected.

- If you smell gas, see flame irregularities, or have safety concerns.

Call a Gas Safe registered engineer or Worcester Bosch support. Tell them you are seeing error 208 (chimney sweep mode) and what steps you have already tried. A qualified engineer will be able to exit service mode properly, diagnose why the boiler entered or will not exit sweep mode, and repair or replace any faulty switches, wiring, code plugs or control units as needed.

Do not attempt in-depth electrical or gas component repairs yourself. Boiler electronics, gas and combustion systems must be handled only by qualified technicians. No price estimates are provided here; contact a Gas Safe engineer for diagnosis and a quote.