Error E.04 – .13

Safety precautions:

- If you smell gas or suspect a carbon monoxide issue, evacuate the property immediately, call the gas emergency number and 999 if required. Do not use the boiler or any gas appliances.

- Turn off electrical supply to the boiler at the isolator/fuse box before opening or inspecting the unit. Turn off the gas supply if you suspect a gas leak and you know how to do so safely.

- Work only within your competence. Do not attempt gas-side or sealed-unit repairs — these must be done by a Gas Safe engineer.

Initial checks a homeowner can do (no tools or minimal skill):

1. Note the error code and display behavior. Take a photo of the fault code and any other lights for the engineer.

2. Try a single reset: press and hold the boiler reset button for the recommended time (usually 3–10 seconds) and allow the boiler to attempt to restart. If the E.04–.13 returns immediately or after a short run, stop and call an engineer. Do not keep resetting repeatedly.

3. Check the flue terminal outside the property for obvious blockages (bird nest, leaves, debris, snow). If blocked, clear only from outside without forcing anything into the flue; if blockage is significant, call an engineer.

4. Listen for unusual noises from the boiler when it tries to run (grinding, screeching or nothing at all). Note any rattles or lack of fan noise.

5. Confirm mains power and gas supply to the house are present by checking other appliances.

Specific diagnostic and (basic) inspection steps (if you are competent and comfortable, and only after isolating electricity and gas):

1. Isolate the boiler electrically and ensure the gas is off. Wait a few minutes for components to cool.

2. Remove the outer casing only if you are confident and the boiler manual shows how. Do not remove sealed covers or attempt gas/combustion component repairs.

3. Visually inspect the fan and surrounding area for obvious debris, loose wires, or disconnected connectors. Look for signs of burning, melted insulation or corroded connectors.

4. If accessible and safe, spin the fan rotor gently by hand to check for free movement. If it is stiff, gritty, or seized, do not force it — this indicates a defective fan motor or blocked rotor and requires replacement.

5. Check wiring harnesses and connectors between the fan and the PCB for secure connection. If you find a loose plug, reconnect it securely. If you find obvious damaged wiring, note its location and do not attempt to repair gas-side wiring yourself — this is for a Gas Safe engineer.

6. Refit the casing, restore power and gas, and attempt a single restart to see if the fault clears. If E.04–.13 returns, stop and call a professional.

When to call a professional and next steps:

- Call a Gas Safe registered engineer if the fault persists after the basic checks, if the fan is seized, if wiring is damaged, or if you are unsure at any point. Repair will often involve replacing the fan assembly or PU (air/gas) unit and testing/commissioning the boiler and flue.

- Do not continue to run or repeatedly reset the boiler; repeated lockouts are a safety risk and can damage components.

- After repair, request that the engineer performs a full combustion and flue check and a carbon monoxide test to confirm the boiler is safe to operate.

Final note: E.04–.13 is a safety-related permanent fault. Homeowner checks are limited to visual inspection, a single reset, and clearing obvious external flue blockages. Any internal fan or wiring fault must be repaired and tested by a Gas Safe engineer.