Vaillant ecoTEC VU 656/4 Installation And Maintenance Instructions Manual

Also see for ecoTEC VU 656/4: Installation manual Operating manual

Contents

49Installation and maintenance instructions ecoTEC 0020029173_01Code Meaning CauseF. 0 Interruption, flow temperature sensor NTC plug not plugged in or has come loose, multiple plug onelectronics not plugged in correctly, interruption in cable harness,NTC defectiveF. 1 Interruption, return temperature sensor NTC plug not plugged in or has come loose, multiple plug onelectronics not plugged in correctly, interruption in cable harness,NTC defectiveF.10 Short circuit flow sensor Short to ground/short circuit in cable harness, NTC defectiveF.11 Short circuit, return sensor Short to ground/short circuit in cable harness, NTC defectiveF.13 Short circuit cylinder sensor Short to ground/short circuit in cable harness, moisture in plug,NTC defectiveF.20 Safety switch-off, temperature limiter Incorrect earth connection between cable harness and boiler, flowor return NTC defective (loose connection), black discharge viaignition cable, ignition plug or ignition electrodeF.22 Safety switch-off, water shortage No or insufficient water in boiler, cable for pump, water pressuresensor or volume flow sensor loose/not plugged in/defective, pumpblocked or defective, pump output too low, non-return valvesblocked/incorrectly installed, minimum quantity of circulationwater not reached, flow sensor defectiveF.23 Safety switch-off: temperature difference too great Pump blocked, insufficient pump output, air in appliance, systempressure too low, flow and return NTC interchangedF.24 Safety switch-off: temperature increase too fast Pump blocked, poor pump performance, air in boiler, installationpressure too low, non-return valves blocked/incorrectly installed,flow and return NTC mixed upF.25 Safety switch-off: Flue gas temperature too high Break in plug connection for optional flue gas safety thermostat,break in cable harnessF.27 Safety switch-off: flame simulation Moisture on electronics, electronics (flame monitor) defective, gassolenoid valve leakingF.28 Failure during start-up: ignition unsuccessful gas meter defective, gas pressure monitor has been triggered, airin gas, gas flow pressure too low,Thermal isolator device (TAE) has been triggered, condensate ductblocked, incorrect gas throttle, error at gas valve, multiple plug onelectronics incorrectly plugged in, break in cable harness, ignitionsystem (ignition transformer, ignition cable, ignition plug, ignitionelectrode) defective, ionisation current interrupted (cable,electrode), incorrect earthing of boiler, electronics defectiveF.29 Failure during operation: re-ignition unsuccessful Gas feed interrupted from time to time, flue gas recirculation,condensate duct blocked, faulty earthing of boilerF.32 Error, fan Plug at fan not correctly plugged in, multiple plug on electronicsnot correctly plugged in, break in cable harness, fan blocked, Hallsensor defective, electronics defectiveF.49 Error, eBUS Short-circuit on eBUS input, eBUS overload or two power supplieswith different polarities on the eBUSF.61 Error, fuel valve control short circuit/short to ground in cable harness for gas valve, gasvalve defective (coils shorted to ground), electronics defectiveF.62 Error, fuel valve switch-off delay delayed shutdown of gas valve, delayed extinguishing of flamesignal, gas valve leaking, electronics defectiveF.63 EEPROM error Electronics defectiveF.64 Error, electronics/sensor Flow or return NTC short circuited, electronics defective -recirculationF.65 Error, temperature of electronics Electronics too hot due to external effect, electronics defectiveF.67 Error, electronics/flame Implausible flame signal, electronics defectiveF.70 Invalid boiler ID Spare part case: Display and electronics changed at the same timeboiler variant not re-setF.71 Error, flow temperature sensor Flow temperature sensor signalling constant value -> flowtemperature sensor defectiveTable 9.4 Fault codes (continued on next page)Troubleshooting 9