Boiler breakdowns are stressful, especially when your heating or hot water cuts out just when you need it most. Modern boilers are built with safety systems that display error codes on the screen whenever something goes wrong. These codes might look confusing at first, but they’re simply the boiler’s way of pointing to the problem.
Some error codes can be fixed with a simple reset or topping up the pressure, but many will need the help of a qualified heating engineer. To make things easier, we’ve put together this guide to some of the most common boiler fault codes across Worcester Bosch, Vaillant, Baxi, and Ideal boilers.
Boiler Error Codes Explained
Error codes fall into different categories. Some are “locking errors,” which mean the boiler has shut down completely for safety and needs resetting after the issue is fixed. Others are “blocking errors,” which temporarily stop the boiler but allow it to try again. In both cases, the code helps you and your engineer work out what’s wrong.
Worcester Bosch Boiler Error Codes
Worcester Bosch boilers often show locking errors, blocking errors, cause codes, or maintenance codes.
- Common Locking Errors
- 9A: Incorrect part fitted.
- B7: Control board needs replacing.
- C6 / C7: Fan running too fast, too slow, or not at all.
- D1: Boiler overheating or sensor problem.
- E2: Flow sensor faulty or disconnected.
- E5 / E9: Heat exchanger overheating.
- EA: Boiler has failed to ignite or the flame has gone out.
- Common Blocking Errors
- A1: Low water in the system – check the pressure gauge and repressurise to 1 bar.
- C1: Fan has stopped.
- EF: Boiler working at minimum level with poor water circulation.
- No Code / 260: Air lock or not enough water in the system.
If you see an EA code or repeated overheating errors, it’s time to call a Gas Safe engineer to investigate further.
Vaillant Boiler Error Codes
Vaillant boilers often use codes starting with F.
- F22: Low water pressure.
- F28 / F29: Ignition fault or flame going out.
- F32: Fan failure or blocked flue pipe.
- F75: No pressure change detected when the pump starts – may point to pump or water pressure issues.
- F76: Heat exchanger overheating.
- F49, F61, F62: Electrical or gas valve faults.
Some codes, like F22 (low pressure), may be resolved by topping up your boiler. Others, such as gas valve or electronics faults, always need a professional.
Baxi Boiler Error Codes
Baxi boilers are also common in homes and often show these codes:
- E119: Low water pressure.
- E133: Failed ignition.
- E125: Overheating.
- E168: Circuit board issue.
- E110: Boiler has overheated.
While topping up pressure may fix E119, issues like ignition failures or overheating need expert attention.
Ideal Boiler Error Codes
Ideal boilers are straightforward but use a mix of letter and number codes.
- F1: Low water pressure.
- F2 / L2: Flame loss.
- F3: Fan fault.
- F4 / F5: Flow or return sensor faults.
- L1: Overheating or no water flow.
- L5: Boiler has been reset too many times.
- L6: False flame lockout.
If your Ideal boiler keeps showing flame loss or overheating errors, call a Gas Safe engineer to prevent repeated breakdowns.
Should You Repair or Replace Your Boiler?
Not every fault means your boiler is beyond repair. Often, a quick fix or a service can solve the problem. But if your boiler is older, breaking down frequently, or showing expensive faults like a failed heat exchanger, replacement may be the smarter option. A qualified heating engineer in Bedford or Milton Keynes will be able to advise on the most cost-effective route.
Boiler Repairs and Installations in Bedford and Milton Keynes
If your boiler is showing an error code, FixBot Ltd is here to help. Our Gas Safe registered heating engineers in Bedford and Milton Keynes provide boiler repairs, servicing, replacements, and new installations.
Whether you need a one-off fix or you’re considering a new boiler installation in Bedford or Milton Keynes, we’ll make sure your home stays warm and comfortable. Call us today on 01234 815101 or fill out our contact form to arrange a visit.
