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boiler service, boiler repair, emergency repair
Worcester Greenstar Highflow 440CDi Boiler Fault Codes
| Code | Description | Check, repair/replace as necessary |
| A1 | Pump dry run detection or Pump is running in air | Check the system pressure, refill if necessary |
| A5 | Tank NTC defect | Check tank NTC sensor and leads, measure resistance across NTC (33.5k- 500) |
| A7 | DHW NTC defect | Check DHW NTC sensor and leads, measure resistance across NTC (33.5k- 500) |
| A8 | EMS communication error | Check electrical connections of EMS controls (if fitted), connections on the control board, replace control board. |
| b1 | Code plug not detected | Insert code plug correctly, test and replace as necessary. |
|
b2,b3,b4, b5,b6 |
Data error | Replace control board. |
| b7 | Burner control error | Replace control board. |
| C6 | Fan defect | Check fan, lead, and connector, replace as necessary. |
| D3 | External temp limiter | Check plug connector ST8, link missing/damaged between 8 & 9 on ST8 . |
| D5 | Condensate pump failure | See condensate pump table. |
| D6 | Internal heat bank overflow | Check system pressure, tank over heat thermostat and leads, and pump operation |
| EA | Flame not detected | Check gas is present and working gas pressure, ignition electrodes and harness, flame sense electrode and harness, and operation of gas valve. Replace as necessary. |
| E2 | Primary NTC defect | Check primary NTC sensor and leads, resistance across NTC should be between 36k to 1k |
| E9 | OH stat tripped |
Check system pressure, over heat thermostat, and pump operation. Check fuse (T1.6A slow blow), replace as necessary. |
| F0 | Internal error | Check all electrical connections, replace board as necessary. |
| F1 | ROM error check | Check all electrical connections, replace board as necessary. |
| F7 | Flame detected after appliance shut off | Check flame sense electrode and harness, and control board for signs of water damage. Replace as necessary |
| FA | Flame detected after gas shut off | Check flame sense electrode and harness, and control board for signs of water damage. Check gas valve operation. Replace as necessary |
| Fd | Reset button pressed | Press reset button again |