Error EA 261

Safety first:

1. If you are not a qualified engineer, do not attempt gas or internal electrical repairs. Work that involves the gas valve, ignition system or control board must be done by a Gas Safe registered engineer.

2. Before any visual checks, switch the boiler off at the programmer and at the fused spur or isolator. Do not isolate the property’s main gas supply yourself.

3. If you smell gas, leave the property immediately and call the gas emergency number.

Initial checks a homeowner can do:

1. Note the displayed fault exactly (EA 261) and the time it occurred. If the boiler also shows a flashing triangle or a three-digit cause code, write that down — it helps the engineer.

2. Perform a single reset: press and hold the reset or ✓ button for about 8 seconds until the display reboots. Wait for the boiler to try to restart. If it clears and the boiler runs normally, monitor it for recurrence.

3. Check whether any recent work was done on the boiler (service, part replacement, or a new HCM/code plug fitted). If the fault began after work, tell the engineer who did the job.

4. Check basic supply items: mains power to the boiler, boiler display/backlight present, and that central heating pressure looks normal on the gauge. Do not attempt to open the boiler yet.

More detailed diagnostic steps (only if you are competent and comfortable with simple visual checks):

1. If you are confident with basic electrical isolation, switch the boiler off at the fused spur and isolate from the mains. Wait a few minutes for capacitors to discharge.

2. Remove the outer casing only if you are competent to do so and the warranty/installer instructions allow. Inspect the HCM / code plug area for obvious signs: loose connector, unseated plug, corrosion, water ingress or damage. If you see obvious corrosion or water, stop and call an engineer.

3. If a connector looks loose and you are competent, you can very gently reseat the HCM/code plug ensuring it sits fully in its socket. Ensure no pins are bent. Replace the casing, restore power, and attempt one reset. If the fault clears, monitor the boiler. Do not repeatedly reset the boiler to force operation.

4. If the HCM was recently replaced or the wrong part may have been fitted (different part number), the system can show EA 261. In that case the correct HCM/code plug must be fitted — this is a job for a Gas Safe engineer.

When to call a professional:

1. If the reset does not clear the code, if the error returns, or if reseating the module is needed but you are not qualified, stop and call a Gas Safe registered engineer. Replacing the HCM, replacing the code plug, or repairing the control box are specialist tasks.

2. If you see water damage, burnt components, or hear unusual electrical noise when the unit attempts to start, switch the boiler off and call an engineer.

3. Provide the engineer with the model, serial number, exact fault code (EA 261) and any cause code displayed, plus any recent service history or parts changes. If the boiler is under warranty, contact Worcester Bosch or your installer first.

Additional notes:

1. Avoid repeated resets — if the fault persists a reset will not fix a genuine HCM fault and could mask the issue. One reset to check is reasonable; repeated attempts are not advised.

2. Keep a record of when the fault occurred and any steps you took. Take a clear photo of the display and the inside (if you opened the casing) to share with the engineer.

3. If you are in doubt at any stage, or the boiler is still under warranty, arrange for a Gas Safe registered engineer to inspect and repair the boiler. Replacement of the HCM or code plug should be undertaken by a qualified engineer.