| Insufficient circulation | Water pressure |
| |
| Bleed heat exchanger |
| Pump operation |
| CH return filter for blockages |
| Circulation around boiler (blockages) |
| ntc temperature sensors |
| Insufficient water (request filling) | Water pressure gauge for correct pressure |
| Check for waterleaks on the entire system |
| CH Flow temp, probe circuit open/ short circuit | Check connections and wiring to temp sensors |
| CH Flow temp, probe circuit open/ short circuit | Resistance values of temp sensors |
| Heating delivery probe problem | Details in maintenance guide in installation manual |
| Floor thermostat contact open | Check terminals TA2 for presence of link wire |
| EEPROM Error | Check the EEPROM connection onto the pcb |
| Communication error | Check connection and wiring onto all devices, main and display pcb |
| Too many (>5) resets in 5 minutes | Identify reason for lockout from table and check for relevant faults |
| No Flame detected | Insufficient working gas pressure |
| 1st Ignition failed | Spark electrode/wiring connectors |
| 2nd Ignition failed | Ignition electrode/wiring connectors |
| Flame cut-off | Spark generator/wiring connectors |
| Check flue system for correct assembly/ termination |
| Check earth |
| Gas valve |
| C02 settings |
| Soft light rate |
| Flame detected with gas valve closed | Ignition electrode/wiring connectors |
| Ignition electrode wiring connection onto main pcb |
| Flame lift | Insufficient working gas pressure |
| Check flue system for correct assembly/ termination |
| C02 settings |
| Thermofuse open | Check wiring and connections to thermofuse |
| Check integriry of main heat exchanger |
| Fan speed error | Check fan |
| Check wiring connections from fan to pcb |