| Error code | Possible fault | Installer action |
|---|---|---|
| E10 | Outdoor Sensor Error | Outdoor sensor fault. Check the sensor and that the IP menu outdoor-sensor value reads correctly. |
| E20 | Central Heating Thermistor Sensor Fault | Check resistance across the sensor is about 12 kΩ at 25 °C. If not, suspect the sensor. |
| E28 | Flue Thermistor Fault | Check the flue sensor value. Check for a blocked flue. |
| E110 | Boiler Overheat Tripped | Check boiler temperature is not over 110 °C; continuity across the overheat stat; pump circulation; clear air from the system. |
| E119 | System Pressure Low (< 0.5 Bar) | Check for leaks; check expansion-vessel charge; add water via the filling loop. Restoring pressure resets the error. |
| E125 | Primary Water Circulation Fault | Check the pump; system full of water; clear air; check for blockages; check thermistors are located correctly. |
| E131 | Flue Overheat Lockout | May follow a power cut — try reset. Flue NTC exceeded 130 °C; check resistance. Possible blocked heat-exchanger waterways. |
| E133 | Ignition Fault | Check wiring, supply pressure, purge air, spark at electrode, electrode condition, gas valve opening, condensate drain. |
| E160 | Fan Fault | Check the fan and cable. Probable fan failure. |
| E161 | Fan Fault | Check the fan and cable. Probable fan failure. |
| E164 | Heating Flow Switch Error (Ireland) / Pressure Sensor Error (UK) | HEa Irish system boilers have flow switches — check switch operation. UK boilers: fit the correct PCB. |
| E167 | PCB Fault | |
| E168 | PCB Lock Out | May follow a power-supply problem. Try reset. |
| E193 | Circulation Fault | If it persists, E125 usually follows. |
Gas work stays with a Gas Safe registered engineer. These steps are guidance from the manufacturer sequence, not a substitute for the handbook.