Fault Codes and Troubleshooting Methods
| LED Fault Indicator | Code Meaning | Possible Cause |
|---|---|---|
| E1* | Fake flame fault, residual flame fault, or ignition failure | Flame signal detected during startup; flame signal detected when combustion stops; no flame detected after ignition. |
| E2* | Overheat fault | Temperature > 90°C, causing the overheat relay to open. |
| E3* | Flue draft pressure fault | Abnormal flue pressure switch or blower operation. |
| E4* | Water flow or pressure fault | Abnormal water flow or water pressure switch. |
| E5 | Valve voltage fault | Voltage detected before startup or loose wiring connections. |
| E6* | Hot water NTC fault | Hot water NTC sensor open-circuit or short-circuit. |
| E7* | Heating NTC fault | Heating NTC sensor open-circuit or short-circuit. |
| E0* | Frost protection activation | Unit shuts down when hot water NTC reads < 2°C; enters frost protection mode when heating NTC reads < 4°C. |
| EB* | Flue gas temperature fault | Exhaust gas temperature too high. |
| EL* | Condensate fault | Condensate drain pipe blocked. |
| EU* | Communication fault | Electromagnetic interference. |
Fault Code: “E0”
- Meaning: Heat exchanger pipe temperature ≤ 2°C
- Possible Cause: Frost protection activated
- Solution: The unit automatically halts all operations and displays “E0” on screen. The fault clears automatically once temperature returns to normal. Frost protection mode activates when heating NTC temperature drops below 4°C.
Fault Code: “E1”
- Meaning: No flame detected after startup or abnormal residual flame signal
- Possible Cause: Ignition failure or false flame detection
- Solution: Power-cycle the unit. If the issue persists, contact an authorized service technician.
Fault Code: “E2”
- Meaning: Overheat protection activated
- Possible Cause: Excessively high temperature (> 90°C)
- Solution: Check for blockages in system piping and filters; restart the unit. If recurring, contact a qualified technician.
Fault Code: “E3”
- Meaning: Flue pressure switch fault
- Possible Cause: Flue pressure switch not closing or blower malfunction
- Solution: Inspect flue exhaust duct for obstructions; have a certified service technician inspect the blower system.
Fault Code: “E4”
- Meaning: Abnormal water flow or pressure switch
- Possible Cause: Low water pressure or restricted water flow
- Solution: Check inlet valve and filter mesh; ensure water pressure > 1 bar. If unresolved, contact a qualified technician.
Fault Code: “E6”
- Meaning: Hot water temperature sensor fault
- Possible Cause: Hot water NTC sensor open-circuit or short-circuit
- Solution: Contact an authorized service technician.
Fault Code: “E7”
- Meaning: Heating temperature sensor fault
- Possible Cause: Heating NTC sensor open-circuit or short-circuit
- Solution: Contact an authorized service technician.
Fault Code: “EA”
- Meaning: Temperature exceeds 90°C
- Possible Cause: Hot water temperature too high
- Solution: Same resolution as for fault code “E2”.