BoilerBuddy · type a code
Got a code on the boiler display? Type it here.
The display on the front of the boiler is showing a code, and you want a calm plain-English answer before picking up the phone. The lookup below matches what you type to the same in-process codes table that powers the per-brand pages, then lands you on the safe-step guide for the family of fault. Pick a code in any UK make — Worcester Bosch, Vaillant, Baxi, Ideal, Viessmann, Glow-worm — works either way.
Search the directory
Find the code on your boiler display
Search the full public fault-code index by code, alias, or manufacturer. Open the matching manufacturer lookup with the code already filled in, or follow the existing safe-step guide where one is mapped.
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Type a code
Got a code on the boiler display? Type it here.
F.22, EA, E20, F1 all work.When to call a Gas Safe engineer
If any of these apply, leave the boiler alone and call a registered engineer.
These are the lines that mean the fault is past the safe-at-home boundary. Any of them — turn the boiler off at the controls and book a Gas Safe engineer:
- You can smell gas, your CO alarm is sounding, or the boiler locks out again the moment you reset it.
- The same code keeps coming back across the day, or it appears next to a second code the display also shows.
When to stop and use the emergency route
For gas, CO or combustion danger, leave first and call 0800 111 999 from outside.
These signals are beyond safe-at-home troubleshooting. Stop using the appliance and leave when appropriate. The National Gas Emergency Service comes before an engineer booking; ordinary faults remain Gas Safe engineer territory:
- Smell of gas, a sounding CO alarm, possible CO symptoms, or a yellow, orange or sooty flame — stop, leave the property, and call 0800 111 999 from outside. Call 999 if anyone is seriously unwell.
- The same code keeps coming back across the day, or it appears next to a second code the display also shows — this is the boiler telling you it cannot resolve the fault itself.
- The pressure-relief valve discharge pipe outside is dripping or spitting, or the boiler is showing a hot-water-side fault code on the display — sealed-component work, registered engineer territory.
Common questions
Three questions homeowners ask most about typing a code in.
A code on the display is a starting point — not a diagnosis. This lookup tells you the family of fault, the safe-at-home check, and the line that means call a Gas Safe engineer. It will not invent a code, will not pin a fault to a specific PCB, and will not promise a price.
Don’t see your code?
If the code on the display isn’t in this lookup — three fall-back routes.
These three routes cover the long tail. Pick whichever fits how confident you are about the code you saw.
was this page helpful?
pick the option that fits. if anything was unclear, send a short note to the team.
Guidance only — a registered engineer makes the final call on every code.