Complete guide to Energy, Ultimate, Betacom, Easicom series fault codes with troubleshooting advice
When your Glow-worm boiler displays an error code, it's alerting you to a problem that needs attention. Use our guide to identify what the code means.
Tip: Glow-worm codes typically start with 'F' followed by numbers (e.g., F.22, F.28, F.75), similar to Vaillant codes.
| Code | Meaning | Quick Fix | DIY? |
|---|---|---|---|
| F1 | Ignition/gas supply fault or low pressure | Check gas supply is on, check pressure gauge, thaw frozen condensate in winter | Partial |
| F22 | Low water pressure - below safe operating level | Top up pressure using filling loop to 1.0-1.5 bar, reset boiler | Yes |
| F75 | Pump/pressure sensor fault - no pressure rise detected when pump starts | Check system pressure, reset boiler | No |
| F24 | Temperature rising too quickly - circulation issue | Check radiators are on, bleed airlocks | Partial |
| F23 | Temperature differential too high | Check circulation, bleed system | Partial |
| F72 | Flow/return temperature discrepancy | Check system circulation, bleed radiators | Partial |
| Code | Meaning | Quick Fix | DIY? |
|---|---|---|---|
| F28 | Ignition lockout - boiler failed to ignite after multiple attempts | Check gas supply is on, thaw frozen condensate pipe in winter, reset boiler | Partial |
| F29 | Flame lost during operation | Check gas supply, thaw condensate pipe if frozen, reset boiler | Partial |
| F27 | Flame sensing fault - flame detected when shouldn't be | Do NOT reset repeatedly - call Gas Safe engineer immediately | No |
| F32 | Fan speed fault | Reset boiler, check flue is clear | No |
| F33 | Air pressure switch fault | Reset boiler, check flue terminal | No |
| F61 | Gas valve control fault | Reset boiler - do not repeatedly reset | No |
| F62 | Gas valve shutoff delay fault | Reset boiler | No |
| Code | Meaning | Quick Fix | DIY? |
|---|---|---|---|
| F5 | Overheat protection activated - boiler too hot | Let boiler cool, bleed radiators, check pump operation | Partial |
| F2 | Fan/air pressure switch fault | Reset boiler, check flue is clear externally | No |
| F83 | Flow/return temperature sensor fault | Reset boiler | No |
| F10 | Flow temperature sensor short circuit | Reset boiler | No |
| F11 | Return temperature sensor short circuit | Reset boiler | No |
| F12 | Flow temperature sensor open circuit | Reset boiler | No |
| F13 | Return temperature sensor open circuit | Reset boiler | No |
| F20 | Overheat protection - safety cutout | Let boiler cool, check circulation | Partial |
| F25 | Flue temperature safety cutout | Let boiler cool, check flue is clear | No |
| Code | Meaning | Quick Fix | DIY? |
|---|---|---|---|
| F63 | EEPROM fault - internal memory error | Reset boiler | No |
| F64 | Electronics/sensor fault | Reset boiler | No |
| F65 | Electronics temperature fault - PCB overheating | Let boiler cool, ensure ventilation | No |
| F70 | Invalid display replacement | N/A - requires correct display | No |
| F71 | Flow temperature sensor fault | Reset boiler | No |
The reset method varies by model:
Warning: If the fault returns immediately after resetting, do NOT keep resetting. This can damage components. Call a Gas Safe engineer.
Our Gas Safe engineers service all Glow Worm models across Harrow and London.