Error 2946 V

Safety precautions:

- Do not attempt to work on gas valves, burner parts, or live wiring unless you are a qualified Gas Safe engineer. Isolate mains electrical power before opening any boiler cover to access internal components. If you smell gas, evacuate and call the gas emergency number immediately.

- Wear basic PPE (safety glasses, gloves) and avoid touching internal electronic components when powered.

Initial checks a homeowner can do:

1. Try a simple reset first: follow your boiler manual reset procedure (press reset button for 3 seconds or turn the temperature dial to the reset position and hold 3 seconds). Wait to see if the error clears and the boiler returns to normal. If the code reappears, further action is needed.

2. Power-cycle the boiler: switch off at the isolator or fuse, wait 30 seconds, and switch back on. Check the display again.

3. Check for any recent work: confirm nobody has recently replaced the HCM, PCB or accessory with an incorrect part. If the boiler was recently serviced or parts changed, that may explain an incompatible code plug.

If you are comfortable accessing the boiler's user panel (only with power isolated and panel removed):

4. Locate the code plug / identification module area as described in the manual or service sheet. Do not touch gas or combustion parts. Visually inspect the code plug and connector for signs of damage, burning, corrosion or loose seating.

5. With power off, gently reseat the code plug: unplug and plug it back in to ensure a good contact. Check that the connector clip or latch is fully engaged. Corroded contacts can sometimes be cleaned with a contact cleaner, but avoid scraping pins; if uncertain, stop and call an engineer.

6. Replace the cover, restore power and try a reset again. If the error clears and the boiler runs normally, monitor for recurrence.

If reseating/resetting does not clear the error or the code returns immediately:

7. Do not attempt to substitute generic electronics yourself. The most likely required action is replacement of the correct code plug/module with the exact part specified for the Greenstar 8000, or diagnosing a faulty HCM or control PCB. An incompatible HCM or wrong code plug will continue to trigger the fault.

8. Note any additional error or cause codes shown on the display and record them; these help the engineer identify whether the code plug is the only issue or if the burner control unit/PCB/HCM is at fault.

When to call a professional:

- If the error does not clear after reset and reseating, or you find damaged components, call a Gas Safe registered Worcester Bosch competent engineer. Replacing the code plug or diagnosing PCB/HCM faults requires correct parts, tools and access to manufacturer service information.

- If the boiler displays other locking faults, flame or gas-related errors, or you smell gas, isolate the appliance and call an emergency Gas Safe engineer immediately.

Final notes:

- Replacing or repairing a code plug should be done by a qualified engineer to ensure the correct part and safe reassembly. After a repair the engineer will reset the boiler and confirm normal operation. Do not attempt gas system repairs or PCB replacements yourself.