Error 2950 B

Safety precautions:

1. If you smell gas, evacuate immediately and call the national gas emergency number — do not stay to investigate.

2. Turn off the boiler and isolate electrical power at the isolator before opening the boiler casing. If you are uncertain about isolating the boiler, stop and call a Gas Safe engineer.

3. Never attempt to strip or alter the gas valve, or carry out live gas pressure testing unless you are a Gas Safe registered engineer.

4. Take photographs of the display and any wiring/labels before touching anything so you can show the engineer.

Initial homeowner checks (safe, simple checks you can do):

1. Reset the boiler once: press and hold the reset button (or follow the manual reset method for your Greenstar 8000) for 3 seconds. Note whether the fault returns immediately or after a short run. If it clears and stays cleared, monitor for reappearance.

2. Check gas supply: confirm other gas appliances (hob, cooker) work. Check the property gas meter and the external gas isolation valve to ensure gas is turned on. If other appliances lack gas, contact your gas supplier.

3. Check the boiler for obvious water ingress, condensation, or corrosion around the ignition area and PCB. Damp can cause intermittent flame sensing faults.

4. Look at the flue terminal outside for obvious blockages or damage — a blocked flue can cause combustion problems. Do not attempt to dismantle the flue.

5. Note exact behaviour: whether the burner attempts to light and then locks out, whether the burner sometimes runs (intermittent), and whether any other error or cause codes are shown in the information menu (press the spanner/return key to read cause codes). Record these for the engineer.

Basic visual diagnostic steps (only if you are competent with simple, dead-unit visual checks):

1. Isolate electrical power and allow the boiler to sit so any residual charge is gone. Remove the front cover per the manual.

2. Visually inspect ignition electrode and lead for cracking, heavy carbon build-up, corrosion, or loose connectors. Also check the ionisation lead and connector to the PCB/ignition module for tightness and corrosion.

3. Check for secure earthing/ground connections on the burner assembly and wiring looms. A poor earth can prevent a correct flame signal. Do not try to rewire or make structural repairs unless you are qualified.

4. If you can gently clean light carbon deposits from the electrode tips with a fine emery cloth or very fine abrasive (with the unit cold and isolated), do so carefully — but do not file, reshape, or bend the electrode; if the electrode is visibly damaged replace it (replacement should be fitted by a qualified engineer unless you are trained).

5. Refit the cover, restore power and attempt another reset to see if the fault persists. If the fault returns, power the boiler down and contact a Gas Safe engineer.

When to call a professional and what they will check (important):

1. Call a Gas Safe registered engineer if the reset does not clear the fault, if it is intermittent, or if you are not confident performing the visual checks. Advise them you have an Error 2950 B (no flame signal) and provide any cause codes recorded from the information menu.

2. The engineer will carry out safe gas pressure checks, test and replace the ignition/ionisation electrodes or leads if faulty, check burner earthing and bonding, inspect the gas valve and its operation, test the ignition module/PCB and replace if needed, and verify flue and combustion. They will also use diagnostic tools to read stored cause codes and run ignition tests.

3. If moisture or PCB contamination is suspected, the engineer will dry and clean components or replace affected parts.

4. Do not let anyone who is not Gas Safe attempt to replace or adjust gas-carrying components.

Extra notes:

- Keep a log of when the fault happens, any preceding actions (power cut, service, heavy rain), and any error sequences — this helps the engineer diagnose intermittent faults.

- If the boiler shows additional codes or a flashing triangle, note both the displayed fault and the three-digit cause code from the information menu and pass these to the engineer.

- In short: perform safe visual and supply checks and a single reset. For electrode replacement, gas valve, pressure checks, PCB faults or persistent/intermittent faults, get a Gas Safe registered engineer to diagnose and repair.