| Display Code | Description | Remedy | Resources |
|---|---|---|---|
| A1 | Pump has run dry or pump has stalled/seized. | Check for water leaks. Free the pump or replace. | Link |
| A7 | Hot water NTC sensor defective. | Check hot water NTC sensor and connecting lead for circuit breaks/short circuits. | Link |
| A8 | Break in communication to TD200 or/and RT10. | Check electrical connections. | Link |
| b1 | Code plug not detected. | Insert code plug correctly, test and replace if necessary. | Link |
| C6 | Fan speed too low. | Check fan lead and connector, and fan; replace as necessary. | Link |
| E2 | CH flow NTC sensor defective. | Check CH flow NTC sensor and connecting lead. | Link |
| E9 | Safety temp. limiter in CH flow has tripped. | Check system pressure, check safety temp. limiters, check pump operation, check fuse on pcb, bleed appli- ance. | Link |
| EA | Flame not detected. | Is gas cock turned on? Check gas supply pressure, power supply, igniter electrode and lead, ionisation sensing electrode and lead, flue duct and C02 level. | Link |
| F0 | Internal error. | Check electrical connector contacts, programmer inter- face module ignition leads are not loose; replace pcb if necessary. | Link |
| F7 | Flame detected even though appliance switched off. | Check electrode assembly, dry pcb. Flue clear? | Link |
| FA | Flame detected after gas shut off. | Check gas valve and wiring to gas valve. Clean conden- sation trap and check electrode assembly. Flue clear? | Link |
| Fd | Reset button pressed by mistake. | Press reset button again. | Link |
| XX / -¦¦- | Siphon fill mode | Wait about 15 minutes. If it continues for more than half an hour, call an engineer. | Link |
Gas work stays with a Gas Safe registered engineer. Some codes only apply to a named range — check the model column.