50 Installation and maintenance instructions ecoTEC sustain 0020253094_05E Overview of fault codesNoteSince the code table is used for various products, some codes may not be visible for the product in question.If faults occur, some of them can be reset. To do so, press and hold the button for three seconds.Fault code Meaning Possible causeF.00 Fault: Flow temperature sensor NTC plug not plugged in or has come loose, multiple plug on the PCB notplugged in correctly, interruption in cable harness, NTC sensor defectiveF.01 Fault: Return temperature sensor NTC plug not plugged in or has come loose, multiple plug on the PCB notplugged in correctly, interruption in cable harness, NTC sensor defectiveF.10 Short circuit: Flow temperature sensor NTC sensor defective, short circuit in the cable harness, cable/housingF.11 Short circuit: Return temperature sensor NTC sensor defective, short circuit in the cable harness, cable/housingF.13 Short circuit: Temperature sensor for thedomestic hot water cylinderApplies to: Product with heating mode onlyNTC sensor defective, short circuit in the cable harness, cable/housingF.20 Safety shutdown: Overheating temperat-ure reachedOverheating temperature reached; check whether water is available andwhether the flow rate is sufficient.Incorrect earth connection between cable harness and product, flow or returnNTC defective (loose connection), stray spark via ignition cable, ignition plugor ignition electrodeF.22 / 0,0barSafety shutdown: Water deficiency in theboilerNo water or insufficient water in the product, water pressure sensor defect-ive, cable to water pressure sensor loose/not connected/defectiveF.23 Safety shutdown: Temperature spreadtoo great (NTC1/NTC2)Pump blocked, insufficient pump output, air in product, flow and return NTCsensors connected the wrong way roundF.24 Safety shutdown: Temperature rise toofastPump blocked, insufficient pump output, air in product, system pressure toolow, non-return valve blocked/incorrectly installedF.27 Safety shutdown: Fault in flame detec-tionMoisture on the electronics, electronics (flame monitor) defective, gas solen-oid valve leakingF.28 Fault: Ignition unsuccessful when startingupGas meter defective or gas pressure switch has triggered, air in gas, gasflow pressure too low, thermal cut-out has triggered, incorrect gas injector,incorrect spare gas valve assembly, fault on the gas valve assembly, mul-tiple plug on PCB incorrectly plugged in, break in cable harness, ignition sys-tem (ignition transformer, ignition cable, ignition plug, ignition electrode) de-fective, ionisation flow interrupted (cable, electrode), incorrect earthing ofproduct, electronics defectiveF.29 Fault: Flame loss Gas supply temporarily stopped, flue gas recirculation, incorrect earthing ofproduct, ignition transformer has spark failureF.32 Fan test function active: Fan speedoutside the tolerance valuesPlug on fan not correctly plugged in, multiple plug on PCB not correctlyplugged in, break in cable harness, fan blocked, Hall sensor defective, elec-tronics defectiveF.46 Short circuit: Temperature sensor at thesolar circuit water inletApplies to: Installed solar set (optional)Sensor defective, short circuit in the cable harness, cable/housingF.49 eBUS fault: Voltage too low Short circuit on the eBUS, eBUS overload or two power supplies with differ-ent polarities on the eBUS (can only be found in the fault report)F.61 Fault: Gas valve assembly control Short circuit/short-to-ground in cable harness to gas valve assembly, gasvalve assembly defective (coils shorted to earth), electronics defectiveF.62 Fault: Gas valve switch-off control Delayed switch-off of gas valve assembly, delayed extinguishing of flamesignal, gas valve assembly leaking, electronics defectiveF.63 Fault: EEPROM Electronics defectiveF.64 Fault: Electronics / sensor / analogue-to-digital converterFlow or return NTC short circuited, electronics defectiveF.65 Fault: Electronics temperature too high Electronics overheating due to external influences, electronics defectiveF.67 Value sent back by ASIC is incorrect(flame signal)Implausible flame signal, electronics defectiveF.68 Fault: Unstable flame (analogue input) Air in gas, gas flow pressure too low, incorrect air ratio, incorrect gas in-jector, ionisation flow interruption (cable, electrode)Electronics defectiveF.70 Invalid product code (DSN) Replace the screen and PCB at the same time without reconfiguring theproduct's Device Specific NumberF.71 Fault: Flow/return temperature sensor Flow temperature sensor specifies the constant value: Flow temperaturesensor incorrectly attached to the flow pipe, flow temperature sensor defect-ive