The short answer
Most Worcester Bosch fault codes fall into three groups: low water pressure, which you can usually fix yourself; ignition and flame faults, which a reset sometimes clears; and part failures, which need a Gas Safe engineer. Below are the codes we see most on Greenstar boilers across Newcastle, what each one means, and what to do. We're a Worcester Bosch accredited installer, so Greenstars are the boilers we work on most.
How Worcester Bosch codes work
A Greenstar shows a two-character code, often with a three-digit cause code after it, such as EA 227. The letters tell you the area of the fault and the number narrows it down. Newer 8000 Style boilers use a four-digit number with a letter, such as 1017 W.
Some faults lock the boiler out until you press reset. Others block it for a short time and it tries again on its own. Codes starting with H are maintenance reminders, and the boiler keeps running.
The common codes, and what to do
| Code | What it means | What to do |
|---|---|---|
| EA 227 | No flame detected after ignition: the boiler tried four times to light and couldn't | Check the gas is on (and the meter has credit), then reset once. If it comes back, book an engineer |
| EA 229 | Flame lost while running. Can be a blocked condensate trap or strong wind into the flue | In freezing weather, thaw the condensate pipe, then reset. Repeated, book an engineer |
| A1 281 | Pump stuck, or running with air in the system. Often low water pressure | Check the gauge and top up to about 1 bar. If the pressure keeps dropping, book an engineer |
| 1017 W (8000 Style) | Water pressure too low | Top up the pressure using the filling loop, following the manual |
| 2964 B (8000 Style) | Flow through the heat exchanger too low | Often low pressure or a blockage in the system. Check pressure, then book an engineer |
| C6 214, 215, 216 | Fan not running, running too fast or too slow | Engineer needed |
| E9 224 | Flue gas thermostat tripped: the boiler has overheated | Engineer needed. Don't keep resetting it |
| H13 | Service reminder from the boiler's timer | Not a fault. Book your annual service |
Code meanings are taken from Worcester Bosch's published fault tables as reproduced by HomeServe and Heatable. Your boiler's manual has the full list for your model.
The two fixes you can safely do yourself
Topping up the pressure. With the boiler cold, the gauge should read around 1 to 1.5 bar. If it's lower, open the filling loop valves slowly until it reaches about 1 bar, then close them. Depending on the model, a Worcester boiler has either an external filling loop or a built-in filling link, and the manual shows which you have. If you're topping up more than once every few weeks, there's a leak or a failing part, and that needs a repair.
Thawing the condensate pipe. In a cold snap the plastic pipe running outside from the boiler can freeze, and an EA code with gurgling is the usual sign. Pour warm, not boiling, water along the outside section, then reset the boiler.
Anything that means taking the casing off is a job for a Gas Safe registered engineer. That's the law, not caution on our part.
How many times should you reset?
Once, maybe twice. A reset clears a one-off glitch. If the same code comes straight back, the boiler is telling you there's a fault, and resetting it over and over can make things worse, especially with overheating codes like E9.
When it's time to call us
A repair starts with a £90 diagnostic visit, and you get a fixed price for the fix before any work starts. Tell us the code when you book, so the engineer arrives with the right parts in mind. See boiler repairs in Newcastle, or find your town: North Shields, Cramlington, Wallsend, Whitley Bay.
If your Greenstar is over 12 years old and the codes keep coming, read repair or replace? first. And if you smell gas, ignore all of the above: call the National Gas Emergency Service on 0800 111 999.
Frequently asked questions
What does EA 227 mean on a Worcester boiler?
The boiler tried to light and didn't detect a flame. Check the gas supply, reset once, and book an engineer if it returns.
What is the reset button on a Worcester Bosch boiler?
On most Greenstars it's a button marked with a flame or the word reset, or a menu option on newer models. Hold it for a few seconds. Your manual shows the exact control.
Can I fix low pressure on a Worcester boiler myself?
Yes. Top it up to about 1 bar with the filling loop, following the manual. If it keeps dropping, book a repair.
What does H13 mean?
It's a service reminder, not a fault. The boiler keeps working. Book your annual service to keep your guarantee valid.