Worcester Bosch boilers are popular and reliable, but knowing the codes empowers you to act fast. The most common Worcester Bosch boiler error codes include EA 227 for ignition or flame problems (often a frozen pipe in winter), low pressure faults like 1017 or CE, and fan-related codes such as C6.
These codes cover everything from easy-to-fix low water pressure to issues needing a Gas Safe engineer.
Worcester Bosch Boiler Error Codes: A Quick Overview
Worcester Bosch boiler error codes use letters and numbers to show exactly what needs attention in your Greenstar models and others.
| Error Code | Concise Description |
| EA 227 | No flame detected after ignition attempts |
| 1017 / CE | Low system water pressure |
| C6 | Fan speed incorrect or fault |
| C7 | Fan not running on startup |
| E9 | Overheat or safety temperature limit tripped |
| A1 | Pump stuck or circulation issue |
| E2 | Flow temperature sensor fault |
| F7 | False flame detected |
| FA | Flame detected after burner off |
| EA / General | Ignition or flame loss |
| D1 | Return sensor fault |
| E5 | Flow temperature too high |
| FD | Power interruption |
| 224 | Safety thermostat activated |
| F0 | Internal control or gas valve error |
This covers the most reported codes across popular Worcester Bosch Greenstar ranges. Check your specific model manual for exact matches.
Worcester Bosch Boiler Error Codes: Causes & How to Fix
Worcester Bosch boiler error codes point to specific everyday issues in your heating system, from pressure drops to component wear. Here are detailed explanations for the most common ones with safe steps you can try.
EA 227 No Flame Detected
This Worcester Bosch boiler error code means the boiler tried to light but could not detect a steady flame. It is one of the most frequent codes, especially in colder months.
Common causes include a frozen condensate pipe, low gas supply, blocked flue, faulty ignition parts, or gas valve problems.
Step-by-step fixes:
- Check other gas appliances like your cooker or hob. If they work, the gas supply to the boiler is likely fine.
- Go outside and inspect the condensate pipe for ice. Wrap it gently with a warm towel or pour lukewarm water over it to thaw. Avoid boiling water or flames.
- Ensure the gas valve near the boiler is fully open.
- Turn the boiler off at the mains, wait 30 seconds, switch it back on, and press the reset button.
- If the code returns after these steps, stop resetting and call a Gas Safe engineer to check electrodes, the burner, and gas valve safely.
1017 or CE Low Water Pressure
This Worcester Bosch boiler error code shows the system pressure has dropped too low for safe running. It is very common and usually straightforward for homeowners to address.
Causes include minor leaks, air in the pipes, or gradual pressure loss over time.
Step-by-step fixes:
- Look at the pressure gauge on your boiler. It should read between 1 and 1.5 bar when cold.
- Find the filling loop, typically a flexible silver hose with two valves under the boiler.
- Open both valves slowly while watching the gauge until it reaches 1.2 to 1.5 bar. Close them tightly.
- Bleed a couple of radiators to remove any air.
- Check for wet spots under pipes or radiators. Reset the boiler and monitor the pressure over the next few days. Repeated drops mean an engineer should find the leak.
C6 Fan Speed Incorrect or Fault
The fan that safely removes gases is not spinning at the right speed. This Worcester Bosch boiler error code protects the system.
Causes include blockages in the flue, a failing fan motor, or wiring issues.
Step-by-step fixes:
- Switch the boiler off at the mains for one minute then restart to clear temporary glitches.
- Check the outside flue terminal for leaves, nests, or debris and clear gently if visible.
- Reset the boiler and test the heating.
- If the fault persists, turn the boiler off and contact a Gas Safe engineer. They will test the fan thoroughly and replace it if needed. Never open the boiler yourself.
E9 Overheat or Safety Limit Tripped
This code means the boiler detected temperatures that are too high and shut down for safety.
Causes often involve poor water flow, air in the system, a faulty pump, closed valves, or sludge in the pipes.
Step-by-step fixes:
- Open all radiator valves fully.
- Bleed radiators starting from the top of the house to release trapped air.
- Check and top up the system pressure if low.
- Let the boiler cool for at least 30 minutes before resetting.
- Run the heating on a low setting. If the code returns, call an engineer for a system check and possible flush.
A1 Pump Stuck or Circulation Issue
The central heating pump is not circulating water properly. This Worcester Bosch boiler error code affects heating performance.
Causes include low pressure, airlocks, a seized pump, or blockages.
Step-by-step fixes:
- Top up the boiler pressure using the filling loop method described earlier.
- Bleed all radiators thoroughly.
- Listen for the pump when heating is called for. If silent or noisy, note it.
- Reset the boiler.
- Persistent issues require an engineer to inspect or replace the pump and clean the system.
For sensor faults, false flame codes, or internal errors, professional help is the safest route.
Replace Your Worcester Bosch Boiler with a Modern, More Efficient Heating System
If your Worcester Bosch boiler is repeatedly displaying error codes, it could be a sign that it’s becoming less reliable. Although many faults can be repaired, recurring problems with ignition, low water pressure, circulation, or fan components can lead to mounting repair costs and unexpected breakdowns that leave you without heating or hot water.
At Eazy Heat, we make upgrading your boiler straightforward. We provide new boiler installations for homeowners and landlords across the UK, with a simple online quotation process, expert guidance, and professional installation from experienced engineers. Every installation is backed by a market-leading 12-year parts and labour warranty, giving you confidence that your new boiler is built to deliver reliable performance for years to come.
Use our online boiler quotation tool today to receive a clear, fixed-price quote in just a few minutes. We’ll help you choose the ideal boiler for your property and arrange a fast, hassle-free installation, so you can enjoy dependable, energy-efficient heating without the inconvenience of recurring boiler error codes.
Frequently Asked Questions
How often should I service my Worcester Bosch boiler to prevent error codes?
Annual servicing by a Gas Safe engineer is recommended. This catches wear early, maintains efficiency, and can support your warranty. Many homeowners find it reduces unexpected faults significantly.
Will a Worcester Bosch error code affect my boiler warranty?
It depends on the cause and whether the boiler was serviced properly. Regular maintenance helps protect your warranty. Always keep service records handy when claiming.
Are Worcester Bosch boilers still a good choice for UK homes in 2026?
Yes, they are reliable with excellent support and long warranties. Many households choose them or upgrade to newer models for better efficiency amid rising energy costs.
Can landlords reset Worcester Bosch error codes themselves before calling help?
Landlords can perform basic safe checks like repressurising, but should arrange a professional inspection promptly for tenant safety and to meet legal requirements.
What is the average lifespan of a Worcester Bosch boiler before faults increase?
Well-maintained units often last 12 to 15 years. After this, error codes may appear more often as parts age, prompting many to consider a replacement for efficiency gains.