BoilerFaultCodes Last 28 days · Real search data
Most-searched boiler fault codes
The fault codes UK boiler owners actually look up — ranked by what's most searched on the site. Each entry links to the full plain-English explanation, repair cost estimate, and severity.
| # | Code | What it means | Severity | Searches |
|---|---|---|---|---|
| 1 | E166 Baxi BBU 45/4 | Your boiler has detected an issue with the internal mechanism that controls the gas supply, meaning it has safely shut itself down to prevent unsafe operation. ~£150-£300 | Emergency | 1 clicks 1 impressions |
| 2 | 9H Ideal Maximiser SE | Your boiler's internal computer has suffered a technical failure and cannot communicate with the rest of the system. ~£250-£450 | High | 1 clicks 1 impressions |
| 3 | 72 Vokera Linea HE | Your boiler is having trouble reading the temperature of the water returning to it, which means it has stopped working to prevent potential damage. ~£120-220 | High | 1 clicks 1 impressions |
| 4 | E10 Remeha Avanta Plus | Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely. ~£0-120 | High | 0 clicks 1 impressions |
| 5 | 1021 B Worcester Bosch Junior 28i | Your boiler is unable to measure the temperature of the water coming out of your taps, which usually means your hot water will be cold or inconsistent. ~£90-160 | High | 0 clicks 1 impressions |
| 6 | 227 V Worcester Bosch Junior 28i | Your boiler is trying to light but cannot detect a flame, which means it has stopped working to keep you safe. ~£150-450 | High | 0 clicks 8 impressions |
| 7 | E40 Alpha CD24 | Your boiler has stopped working because the amount of water in your central heating system is too low. ~£60-120 | High | 0 clicks 1 impressions |
| 8 | E31 Alpha Pro Tec Plus | Your boiler has lost its connection to the remote wall controller, meaning it cannot receive signals to adjust your heating or hot water settings. ~£90-180 | Medium | 0 clicks 2 impressions |
| 9 | E21 Ariston Clas One | Your boiler has detected that the electricity supply wires are connected in the wrong order, preventing it from functioning safely. ~£90-180 | High | 0 clicks 1 impressions |
| 10 | A40 Ariston Bravo 24 MFFI | Your boiler's main control unit has identified an internal electronic error and is preventing the system from starting to ensure your safety. ~£250-450 | High | 0 clicks 1 impressions |
| 11 | A10 Ariston E-Combi One Combi | Your boiler has detected an issue with the ignition process and is currently failing to light the burner to provide heat or hot water. ~£150-300 | High | 0 clicks 1 impressions |
| 12 | EE 0066 Ariston E-Combi One Combi | Your boiler has lost the signal from the sensor that monitors the water temperature, causing it to stop heating your home to prevent potential overheating. ~£120-180 | High | 0 clicks 1 impressions |
| 13 | A01 Ariston Genus One 24 | Your boiler is trying to start up but is failing to light the flame, so it has shut itself off to prevent a build-up of unburnt gas. ~£120-250 | High | 0 clicks 1 impressions |
| 14 | 5 P 2 Ariston HS Premium | Your boiler tried to light the gas flame to start heating your home but failed to do so on its first attempt. ~£120-250 | High | 0 clicks 1 impressions |
| 15 | 18 Atag E Range | Your boiler has shut down because the water inside the unit has reached a temperature that is too hot to operate safely. ~£120-350 | High | 0 clicks 1 impressions |
| 16 | Block 11 Atag E Range | Your boiler has detected that the water inside is heating up much too quickly compared to how fast it is moving around your pipes, so it has temporarily paused your heating to prevent internal damage. ~£150-300 | High | 0 clicks 1 impressions |
| 17 | 108 Atag iC Economiser Plus | Your boiler has stopped working because the water pressure is too low and needs to be topped up. ~£0-120 | High | 0 clicks 1 impressions |
| 18 | 1P4 Atag iC Economiser Plus | Your boiler has detected that the water pressure is getting too low and needs a top-up to prevent it from shutting down. ~£0-80 | Low | 0 clicks 1 impressions |
| 19 | 117 Atag iR Regular | Your boiler has detected that the water pressure is too high, which has caused the system to shut down for safety. ~£80-250 | Emergency | 0 clicks 1 impressions |
| 20 | Error 28 Atag Q 30CR | Your boiler has stopped working because it cannot detect that the internal fan is spinning, which is necessary for safe operation. ~£180-350 | High | 0 clicks 6 impressions |
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