Error E09

Safety precautions:

- If you smell gas, stop immediately, do not operate electrical switches, evacuate the property and call the gas emergency number. Do not attempt any checks or repairs.

- Isolate electricity to the boiler before touching any wiring or removing covers. If you are not competent with electrics, do not open the boiler.

- Do not attempt to work on the gas supply, gas valves, or internal sealed components unless you are a Gas Safe registered engineer.

Initial homeowner checks (safe, non-intrusive):

1. Note the exact error code and model plate information for the engineer. Take a photo of the display if helpful.

2. Try a controlled reset: switch the boiler off at the programmer and isolate switch, wait 30 seconds, then switch back on. See if the error clears. Persistent E09 indicates a real wiring/valve issue.

3. Check other gas appliances to confirm the gas supply is present (e.g., light a gas hob). If there is no gas supply to the property, contact your gas supplier; do not attempt internal boiler repairs.

4. Visually inspect any external wiring to the boiler that you can see without removing covers (room thermostat, external programmers, and visible cable entries). Look for obvious loose connections, chewed or damaged cable, or signs of water ingress. Do not remove boiler panels unless you are competent and safe to do so.

5. Check the boiler wiring center cover for obvious signs of damage at a glance: burn marks, melted insulation or corrosion. If you see these, power down and contact an engineer.

Diagnostic steps for a competent person only (do not attempt if unsure):

1. If you are a qualified electrician or heating engineer, isolate electrical supply and remove the boiler casing to inspect the gas valve connector and PCB plug for loose pins, corrosion, or damaged wires. Re-seat any multi-pin connectors and check terminal screws are tight.

2. With power isolated, check continuity of the wiring loom to the gas valve and inspect earths.

3. If you have the skills and safely can re-apply power, a qualified person can test for the correct control voltage to the gas valve while calling for heat. If the PCB is sending the correct voltage but the valve does not respond, the valve itself is likely faulty. If no voltage is present, suspect a PCB or wiring fault upstream.

4. Do not attempt to dismantle or repair the gas valve. Valve replacement, combustion checks and any gas control adjustments must be done by a Gas Safe engineer.

When to call a professional:

- If E09 remains after a reset and the simple visual checks above, book a Gas Safe registered heating engineer. This code involves the gas control circuit; it requires specialist testing, safe isolation procedures, possible replacement of wiring, connectors, the gas valve or PCB, and gas-tightness and combustion testing after repair.

- If you see burn marks, damaged insulation, or water damage inside the boiler, power down and call an engineer immediately.

What the engineer will likely do:

- Carry out safe electrical and gas isolation, inspect and test wiring and connectors, measure control voltages, test gas valve operation, and if necessary replace the valve or PCB. They will also perform safety and combustion checks and reset the boiler into service.

Final note:

- Do not attempt to repair or replace gas valves, internal wiring or PCB components yourself. For any gas-related or persistent lockout faults, always use a Gas Safe registered engineer to ensure safe, correct repair and certification.