The most common Worcester boiler error codes include EA for no flame detected, A1 showing pump or circulation issues, E9 for overheating, and C6 for fan problems. These often appear because of simple things like low system pressure, a frozen condensate pipe in winter, or air in the radiators, but when the same code keeps coming back it can mean your boiler is getting older and may need more than a quick fix.
We’re Clever Energy Boilers, Gas Safe registered and accredited Worcester Bosch installers in Bingley, covering Yorkshire and the Humber, the North West and the Midlands. This guide lists the Worcester Bosch error codes people search for most, explains each one in plain English and links to a full guide for it. DIY steps appear only where they’re safe, such as topping up pressure or thawing a frozen condensate pipe. If your Worcester is an older boiler showing error codes, a replacement Worcester Bosch is the better option longer term for efficiency and to save on repair bills.
How To Read A Worcester Bosch Error Code On Your Display
Worcester displays show codes in a few different ways, depending on the model. Knowing which one you are looking at makes the rest of this page far easier to use.
- Locking errors flash a code with a warning triangle, and a three-digit cause code shows alongside it. The boiler stays off until it is reset.
- Blocking errors show no code. The boiler stops, and pressing the spanner or return button reveals the cause. It restarts once the problem clears.
- Maintenance codes start with H. The boiler still runs but needs attention.
- Two-part codes such as EA 227 or F7 228 appear on Si and CDi Compact models. The letters are the fault group and the number is the cause inside it. Greenstar i and CDi Classic models often show only the letters, and the Greenstar 8000 Style shows a number with a letter beside it.
If you ever smell gas, switch nothing on, open windows, turn the gas off at the meter and call the National Gas Emergency Service on 0800 111 999. Anything involving the gas valve, flue, fan, electrodes or sensors is work for a Gas Safe registered engineer, and the casing should stay on.
Worcester Boiler Error Codes: Quick Index
Worcester boiler error codes give you an instant picture of what is happening inside your appliance so you can take the right steps and keep your home warm and comfortable all year round. Codes with a full guide are linked.
| Error code | Plain-English meaning | Full guide |
|---|---|---|
| EA | No flame detected after ignition | EA fault code |
| 227 (EA 227) | No flame signal after ignition, the cause code shown with EA | Worcester 227 fault code |
| 228 (F7 228) | A flame signal when there is no flame | Worcester 228 fault code |
| 229 (EA 229) | Flame lost while running; some sources link it to a frozen condensate pipe | Worcester 229 fault code |
| A1 | Pump stuck, running dry or low water in the system | Worcester A1 fault code |
| A7 | Domestic hot water sensor fault | Covered below |
| C1 | Fan stopping during operation | Covered below |
| C6 | Fan speed fault | Worcester C6 fault code |
| C7 | Fan not running on start-up | Covered in the table only |
| D1 | Return temperature sensor fault | Worcester D1 fault code |
| D5 | Blocked or frozen condensate, or condensate pump failure on some models | Worcester D5 fault code |
| E9 | Overheating; safety limiter tripped | Worcester E9 fault code |
| E9 224 | Maximum or flue gas thermostat overheat | Worcester 224 fault code |
| FA | Flame detected after the gas valve closed | Worcester FA fault code |
| 9U | Control box or module defective | Covered below |
| FD | Power interrupted or reset pressed | Covered in the table only |
Why The Same Worcester Error Code Can Mean Different Things
A code is not always identical from one Worcester to the next. C6 is a fan running too fast on some Compact models, too slow on the CDi Classic Combi and a general fan defect on the Highflow. A1 can mean a stuck pump, air in the pump or low water depending on the model, and E9 splits into several numbered causes. Published explanations also differ from site to site, so treat any list, ours included, as a starting point.
The safest approach is to write down the full code, including any number after the letters, and check it against your boiler’s manual before acting.
Worcester Boiler Error Codes: Causes & How to Fix
Each Worcester boiler error code points to one clear part of your system that needs checking so you can sort the problem safely and get your heating back on track quickly.
Worcester Boiler Error Code EA: No Flame Detected
The EA error code on Worcester boilers means the burner has tried to light but the boiler cannot sense a flame, so it has locked out for safety and left you without heating or hot water.
This fault is often caused by a temporary gas supply issue, dirty ignition electrodes, a problem with the gas valve, or a blocked condensate pipe during cold weather.
Here is how to fix it step by step:
- Check that your gas meter and the boiler gas isolator valve are both turned fully on.
- Press the reset button on the boiler once and watch to see if it tries to ignite.
- If it fails again, turn the boiler off at the mains for thirty seconds then try resetting once more.
- If you are in Yorkshire or the North West and it is freezing outside, gently thaw any external condensate pipe with warm water.
- Test another gas appliance in the house to rule out a wider supply problem.
- If the code returns straight away, call a Gas Safe registered engineer to clean the electrodes or check the gas valve.
Want the full detail? Read our EA fault code guide, or the narrower 227 fault code guide if your display shows EA 227.
Worcester Boiler Error Code A1: Pump Stuck, Running Dry Or Low Water
A1 means the boiler has detected a pump problem. Often the cause is low pressure, air in the system or a pump that has seized. Check the pressure gauge first: a cold system should read roughly 1 to 1.5 bar. If it is low, switch the boiler off, connect the filling loop, open the valves slowly until the needle reaches about 1.2 bar and close them firmly. If the pressure keeps falling, there is a leak. A pump that still will not run needs an engineer. Read the full Worcester A1 fault code guide.
Worcester Boiler Error Code E9: Overheating And Safety Limiter Faults
E9 means the water got too hot and a safety limiter shut the boiler down. Low pressure, poor circulation, sludge or a faulty sensor are the usual causes. Check and top up the pressure, make sure radiator valves are open, let the boiler cool and reset once. If E9 returns, stop. The numbers after it, such as 219 or 224, identify the exact cause. See the Worcester E9 fault code guide and the 224 fault code guide.
Worcester Boiler Error Code C6: Fan Speed Fault
C6 means the fan is not running at the speed the boiler expects. The direction varies by model, and the cause is usually a worn fan, a damaged lead, or a restricted flue. There is very little to do yourself beyond looking at the flue terminal from the ground and resetting once. Check that your carbon monoxide alarm works. Read the full Worcester C6 fault code guide.
Worcester Boiler Error Codes 227, 228 And FA: Flame Faults
These three belong together. 227 means no flame was detected after ignition, 228 means the boiler senses a flame that is not there, and FA means a flame was detected after the gas valve closed. All three are safety lockouts. Basic checks cover the gas supply, pressure and condensate pipe, but valves and sensors are for a Gas Safe registered engineer.
Worcester Boiler Error Codes 229 And D5: Condensate And Lost-Flame Faults
In cold weather a frozen condensate pipe is a common trigger. Pour warm, never boiling, water along the pipe from the end towards the boiler, wait ten minutes and reset once. See the 229 fault code guide and the D5 fault code guide. On a CDi Highflow, D5 can mean a condensate pump failure instead.
Worcester Boiler Error Code D1: Return Sensor Fault
D1 points to the return temperature sensor, commonly on Si and CDi Compact boilers. D1 240 and D1 286 mean different things, so note the number. The sensor is a job for an engineer. Details are in our D1 fault code guide.
Worcester Boiler Error Code A7: Domestic Hot Water Sensor Fault
The A7 error code signals a problem with the sensor that measures hot water temperature, so you may lose hot water even though heating still works.
Causes include a faulty sensor, wiring issues, or limescale affecting the sensor in hard water areas like parts of the Midlands.
The fix process is:
- Note the code and turn the boiler off at the mains for five minutes.
- Restart and see if the code clears.
- If it returns, a Gas Safe engineer must test and replace the sensor.
Worcester Boiler Error Code C1: Fan Stopping During Operation
The C1 error code means the fan starts but then stops while the boiler is running, triggering a safety lockout.
It is often linked to the same issues as C6, such as fan wear, electrical faults, or flue restrictions.
Here is what to do:
- Power the boiler off completely.
- Check the flue for any visible debris.
- Restart after five minutes.
- Persistent C1 faults need a professional to inspect the fan and wiring.
Worcester Boiler Error Code 9U: Control Box or Module Defective
The 9U error code indicates a problem with the main control box or heat control module that runs the entire system.
This can be caused by electrical surges, damp inside the boiler, or the module simply wearing out after many years of daily use.
You cannot fix this yourself, so the steps are:
- Turn the boiler off at the mains for five minutes then back on to see if it clears.
- Note the exact code shown.
- If it returns, book a Gas Safe engineer to test and replace the module if needed.
Persistent Worcester boiler error codes often mean your current appliance is under extra strain and could lead to bigger repair bills or a sudden breakdown when you need warmth most.
Should You Reset A Worcester Boiler Error Code?
Once, yes, after you have done the safe checks: gas supply, pressure gauge and a frozen condensate pipe. If the code comes back, stop. Repeated resets only keep restarting a boiler that has a fault, and they can hide a failing part. Advice on how to reset varies. Some guides say to hold the reset button for around eight seconds, which on some boilers restores factory settings, so check your manual first. Never remove the casing.
Worcester Error Codes Keep Returning? A New Boiler Could Save You Money
If the same Worcester boiler error codes keep coming back, repeated callouts and replacement parts can soon add up. Ongoing faults are often a warning that the boiler is becoming less reliable and may be approaching the end of its serviceable life.
Upgrading to a modern, energy-efficient replacement can improve performance, reduce monthly energy costs, and give you dependable heating and hot water backed by strong warranty cover through Clever Energy.
At Clever Energy Boilers, we specialise in boiler installations across the North West, Yorkshire, and the Midlands, helping homeowners and landlords replace unreliable systems with efficient long-term solutions. Whether your current boiler is causing frequent disruptions at home or creating maintenance issues in a rental property, our team offers clear advice and free, no-obligation quotes.
Request your free boiler quote today.
See our Worcester Bosch boiler installation service, or get your fixed price online. Boilers over 8 years old are less efficient, and for an older Worcester showing repeat codes a new Worcester Bosch is the best option.
Worcester Boiler Error Codes FAQs
What does the number after a Worcester error code mean?
It identifies the exact cause inside the fault group. In EA 227, EA is the group (no flame detected) and 227 is the specific cause. Compact models show both parts; others may show only the letters.
Can I reset my Worcester boiler every time an error code shows?
No. Reset once after the safe checks. If the same code returns, stop resetting and have a Gas Safe registered engineer look at it.
Is a Worcester boiler error code dangerous?
The lockout itself is the safety system working. A smell of gas is not: switch nothing on, ventilate and call 0800 111 999. Flue, fan and gas valve faults also justify checking your carbon monoxide alarm.
Which Worcester error codes can I fix myself?
Only the simple ones: low pressure (top up to about 1 to 1.5 bar) and a frozen condensate pipe (thaw with warm water). Everything involving the gas valve, fan, sensors or electrodes needs a Gas Safe registered engineer.
Is it worth repairing an older Worcester that keeps showing error codes?
Usually not once the boiler is over 8 years old. Repeat codes point to ageing parts, and a new Worcester Bosch is more efficient and ends the cycle of repair bills.