Error 2 flashes 5 seconds off

Safety first

1) If you smell gas: evacuate the property immediately, do not operate electrical switches, open windows and doors, call the gas emergency service and a Gas Safe engineer. Do not attempt any checks.

2) If you do not smell gas, switch off the boiler at the programmer or isolator and leave it off until you have read the steps below. Only carry out visual checks that do not expose you to live gas/electrical parts.

Initial simple checks a homeowner can safely do

1) Record the fault pattern and any other lights or codes. Note when it happens (during hot water, during heating, after a restart) and whether the lockout is persistent or intermittent.

2) Check the boiler pressure gauge. If pressure is very low (below ~0.7 bar) top up the system following the boiler handbook—low pressure can cause strange behaviour on some models. Re-test the boiler.

3) Check the external gas supply: are other gas appliances working? If there is no gas to the house, contact your gas supplier.

4) Inspect the flue terminal outside for obvious blockages (birds’ nests, debris) from ground level only. Blocked flues can affect combustion and cause the burner to extinguish.

5) Check for condensation or water ingress around the appliance or the ignition/earth lead area (only visually). Water or heavy deposits on the electrode assembly can stop ionisation.

6) If it is safe and your boiler manual permits, you may attempt a single reset following the instructions on the boiler control knob or handbook. Do not repeatedly reset the boiler if the fault returns. Note: some official guidance advises not to reset EA-type flame/ionisation errors and to contact a Gas Safe engineer instead.

Further diagnostic steps (do not attempt if you are not competent or if it involves removing the burner or gas connections)

1) If you are experienced and comfortable isolating electrical power, switch off the mains and remove the outer casing only to inspect for loose or damaged wiring to the ignition/ionisation electrode and the electrode lead to the burner—only if you know what you are doing. Do not disturb gas fittings. Loose or corroded connections can cause intermittent ionisation loss.

2) Look for obvious damage or heavy soot on the electrode. A heavily soiled or cracked electrode/lead will need replacement by an engineer.

3) If the fault occurs after the boiler has been running for a while, note whether it coincides with a change in fan speed/noise or power blips—this can point to fan, PCB or gas-valve issues.

4) Log the fault frequency and any patterns (time of day, when heating calls, after power cuts). This information helps an engineer diagnose intermittent faults.

When to call a Gas Safe engineer

1) Call a Gas Safe registered engineer immediately if the fault persists after the safe checks above, if the fault repeats, or if you are not confident performing visual checks. The likely professional fixes include cleaning or replacing the ignition/ionisation electrode and lead, checking/replacing the flame-sensing circuit, testing/replacing the gas valve or control module, checking fan and flue/airflow and testing the PCB and wiring.

2) Tell the engineer the exact fault pattern (2 quick flashes, 5s off) and any observations (gas smell, flue blockage, when it happens). This saves diagnostic time.

3) Do not attempt to replace or adjust gas valves, the burner assembly, or internal control boards yourself. These are gas and electrical safety items and must be handled by a Gas Safe qualified engineer.

Final notes

- Treat loss of ionisation as a safety lockout and do not ignore it. A single, cautious reset may be acceptable if there is no gas smell and your manual permits, but repeated resets are unsafe and not a substitute for a proper repair.

- Keep records of fault occurrences, resets and any observations to give to the engineer; this helps speed up repair and correct diagnosis.