Error 226

Safety precautions:

1) Do not open the boiler casing or attempt to access internal gas or ignition components unless you are a qualified Gas Safe registered engineer. Working on gas appliances or mains-voltage wiring is dangerous.

2) Before touching connectors or the control area, turn off the electrical supply to the boiler at the fused spur or mains switch to avoid electrical shock. Wait a minute for capacitors to discharge.

3) If you smell gas or suspect a gas leak, evacuate the property, call your gas emergency number and do not operate electrical switches.

Initial homeowner checks you can do:

1) Note the exact display and any other codes shown. Write down when the fault appeared and any recent activity (e.g., an engineer attended, a diagnostic tool was used, recent power cuts).

2) Look at the boiler control area and check whether a diagnostic/service tool or leads are currently connected to the service port. This is often the cause of a 226 code.

3) Check basic boiler conditions: confirm the boiler has power (display present), check central heating demand (thermostat/roomstat setting), and glance at the system pressure gauge—if pressure is very low (<1 bar) the boiler may also refuse to operate (although this is not the specific 226 cause).

Specific diagnostic and fix steps:

1) If a diagnostic or service tool is attached, isolate the boiler electrical supply at the fused spur or mains, then carefully disconnect and remove the service tool from the boiler service port. If an external engineer left the tool connected, contact them for confirmation before removing it if possible.

2) Restore power to the boiler and perform a reset. Use the boiler’s front panel reset button if present (follow the boiler user manual for the correct reset action), or switch the boiler off at the fused spur, wait about 30 seconds, then switch back on. Do not press reset repeatedly—one controlled reset is sufficient.

3) After reset, observe the display. If the 226 code clears and the boiler returns to normal operation, monitor the system for a while (check heating and hot water cycles). Note any reappearance of the code.

4) If the 226 code returns immediately or the boiler does not clear the lockout after removing the tool and resetting, do not attempt further internal diagnostics. Record any additional fault codes displayed and any unusual behaviour (no ignition, fan running, unusual noises) to report to an engineer.

5) If you did not find a diagnostic tool connected but the boiler still shows 226, it may indicate a retained service-mode flag or an internal control fault. In that case, call a Gas Safe–registered Worcester Bosch engineer to fully diagnose and clear the lockout and check control hardware and software.

When to call a professional:

1) Call a Gas Safe–registered engineer if the fault re-occurs after the reset, if other fault codes appear, if the boiler will not reset, or if you are unsure whether a service tool has been attached by a previous engineer.

2) Always call a professional for any repair work inside the boiler, for gas or ignition system faults, or when replacement of control modules or sensors is required.

Additional notes:

1) If an engineer recently attended and connected a service tool, contact that engineer or their company first; they may be able to clear the lockout remotely or advise whether the tool was left in a blocking mode intentionally.

2) Keep a record of the fault code, time and any actions taken—this helps the attending engineer diagnose the issue more quickly.

3) Do not repeatedly reset the boiler more than once or twice in a short period; repeated resets can mask an underlying fault and may leave the system unsafe. If the basic removal-of-tool and reset does not fix it, arrange for a qualified service visit.