An FA on a Worcester Bosch display means the boiler still senses a flame after the gas valve has closed, which is the sort of fault that deserves a careful response. We’re Clever Energy Boilers, Gas Safe registered and accredited Worcester Bosch installers based in Bingley, covering Yorkshire and the Humber, the North West and the Midlands. If your Worcester is an older boiler showing error codes, a replacement Worcester Bosch is the better option longer term for efficiency and to stop the repair bills adding up.
This one is different from most codes because the fix sits with the gas valve. We’ll explain the code, the two numbers you may see alongside it, and what is and isn’t sensible to attempt yourself. Spoiler: very little of it is DIY, and we’ll say why.
What does the FA fault code mean on a Worcester Bosch boiler?
FA stands for a flame or ionisation signal detected after the gas supply should have shut off. Put simply, the boiler finished heating, closed the valve, and its sensor insists something is still burning.
You may see a number with it. FA 306 points to a false flame after the burner has stopped. FA 364 on the Si Compact is a failed leak test on the second gas valve, known as EV2. On the Greenstar 8000 Style the same fault is shown as 306 with a letter, and the air and gas ratio control valve is the likely culprit.
What causes a Worcester FA fault?
This is where the valve takes centre stage:
- A gas valve that isn’t sealing properly, so gas keeps reaching the burner
- A failed leak test on the second valve (FA 364)
- A fault in the flame sensing, so the boiler reads a flame that has really gone out
- Residual heat or moisture confusing the sensor, in some cases
Worcester models differ here, so the number after FA matters. Write down what your display shows before you speak to anyone.
Is a Worcester Bosch FA error code dangerous?
It’s one to take seriously. The boiler has shut down, which is correct, but an FA can mean a gas valve isn’t closing fully. Leave the boiler off. If you smell gas, open doors and windows, avoid switches and naked flames, turn the gas off at the meter and call the National Gas Emergency Service on 0800 111 999.
If you have a carbon monoxide alarm, check that it’s working. Any combustion fault is a good reminder to test it.
What should I do about a Worcester FA fault?
Here’s the honest answer: not much yourself. Gas valves, leak tests and sensors are all Gas Safe registered engineer territory, and tampering with them is dangerous. What you can do:
- Note the full code, including any number such as 306 or 364.
- Check the pressure gauge. If it has dropped below 1 bar, top it up to about 1 to 1.5 bar using the filling loop, with the boiler switched off.
- Press reset once to see whether it was a one-off.
- If it returns, leave the boiler off and arrange for a Gas Safe registered engineer to inspect it.
Resist the urge to keep resetting. With a possible valve fault, repeated restarts aren’t worth the gamble.
Why does the FA error keep coming back on a Worcester?
A valve that sticks sometimes is likely to stick again. It may pass a leak test on a mild day and fail on the next cold start, which makes the code look random. If you’ve reset an FA more than once, treat it as a genuine fault rather than a glitch.
Should I replace my Worcester Bosch instead of chasing the FA fault?
Gas valve faults are one of the clearest cases for replacement on an older boiler, because the part is among the pricier ones and the boiler around it is the same age. It makes sense to replace if:
- The boiler is over 8 years old
- You’ve had other faults over the past year or two
- The valve is the failed part, as it often is on this code
- You want to stop worrying about a boiler you don’t trust
Our new boiler cost guide gives realistic figures, and a modern Worcester Bosch is far more efficient than the unit it replaces.
Book a new Worcester Bosch with Clever Energy
We install across Yorkshire and the Humber, including Leeds, Bradford, Hull, Sheffield, Doncaster and York, throughout the North West from Liverpool to Blackpool and Lancaster, and across the Midlands in Leicester, Wolverhampton, Stoke-on-Trent and beyond. Find out more about Worcester Bosch boiler installation or get your fixed price online. If you’d like to discuss a new boiler, call 0330 055 2210 on weekdays from 8am to 8pm, or at the weekend between 10am and 4pm.
Worcester Bosch FA fault code FAQs
What is the difference between the FA 306 and FA 364 Worcester error codes?
FA 306 is a false flame detected after the burner stops. FA 364 is a failed leak test on the EV2 gas valve, seen on the Si Compact. Both point at the gas valve area.
Can I carry on using my Worcester with an FA fault code?
We’d say no. Leave it switched off until a Gas Safe registered engineer has checked it, because the code relates to gas valve behaviour.
Is the FA error the same as the Worcester EA code?
They sit at opposite ends of the same sequence. EA is no flame when there should be one, while FA is a flame when there shouldn’t be one. Our EA guide covers the first.
Will resetting clear a Worcester FA fault?
It may clear once if the cause was momentary. If the code returns, resetting only delays the problem, and a possible valve fault shouldn’t be left.
Is a new Worcester Bosch worth it after an FA error code?
On an older Worcester, usually yes. The failed part is a costly one, and the boiler’s age means other faults often follow.
More Worcester Bosch error codes
FA belongs with the other flame codes in the set. Before this one, have a look at the Worcester Bosch 228 fault code; after it, the Worcester Bosch 229 fault code covers the next code in the set. The full list sits on our Worcester boiler error codes guide.
