The 5 Most Common Fault Codes for Worcester Boilers

It’s never convenient when your boiler breaks down, especially during the colder months. If you have a Worcester boiler, don’t panic when fault codes appear—they’re there to help you identify the problem quickly, so you can get it fixed.

Whether you’re facing no heating, no hot water, or something more serious, this post covers the five most common Worcester boiler fault codes and how to address them.

EA – Ignition Failure

An EA fault code indicates your Worcester boiler is struggling to ignite. This could be due to an insufficient gas supply, a blocked flue, or a faulty ignition electrode. It’s a common problem that can leave you without heat or hot water.

Solution:

  • Ensure the gas supply is on and working. If you use a prepayment meter, check that it has credit.
  • Make sure the flue (which vents exhaust gases) isn’t blocked.
  • Try resetting the boiler according to the manual. If the issue persists, contact a Gas Safe registered engineer.

A1 – Low Water Pressure

The A1 fault code signals low water pressure inside the boiler, often disrupting heating and hot water. This issue is especially common in colder months.

Solution:

  • Check the pressure gauge—it should read between 1 and 1.5 bar.
  • If the pressure is low, use the filling loop to top it up as per the boiler manual.
  • If the pressure keeps dropping, there might be a leak. Contact a heating engineer.

E9 – Overheating

An E9 code means your boiler is overheating. This can be caused by system blockages, air in the radiators, or a faulty pump.

Solution:

  • Bleed your radiators to release any trapped air that might cause overheating.
  • Check if the pump is circulating water. If it’s noisy or not working, it may need replacement.
  • If the problem continues, call an engineer to inspect for blockages or other internal issues.

C6 – Fan Fault

The C6 fault code signals a problem with the boiler’s fan, which expels harmful gases through the flue. If the fan fails, the boiler might shut down for safety reasons.

Solution

  • This issue requires professional attention. A Gas Safe engineer should inspect the fan to determine whether it needs repair or replacement.
  • Never attempt to fix the fan yourself—it’s dangerous.

D1 – Sensor Failure

A D1 fault code points to an issue with one of the boiler’s temperature sensors. These sensors regulate water temperature, and if faulty, can cause the boiler to overheat or shut down.

Solution:

  • Try resetting the boiler. If the code reappears, call a Gas Safe engineer to check the sensors. They might need replacing.

Dealing with boiler fault codes can be stressful, but understanding what they mean and how to fix them can save both time and hassle. For more complex issues, it’s always safest to contact a qualified professional—particularly for gas-related faults, which must be handled by a Gas Safe engineer.

By keeping up with regular maintenance and addressing fault codes early, you can extend your boiler’s lifespan and ensure your home stays warm and cosy. Scheduling annual services and staying alert to recurring issues can also help prevent costly breakdowns and unexpected repairs.