Vaillant ecoTEC sustain 24 Installation And Maintenance Instructions Manual

Also see for ecoTEC sustain 24: Operating instructions Installation and maintenance instructions

Appendix40 Installation and maintenance instructions ecoTEC sustain 0020253094_01Fault code Meaning Possible causeF.71 Fault: Flow/return temperature sensor Flow temperature sensor specifies a constant value: Flow temperaturesensor incorrectly attached to the flow pipe, flow temperature sensor de-fectiveF.72 Fault: Deviation in the water pressuresensor/return temperature sensorFlow/return NTC temperature difference too great → flow and/or return tem-perature sensor defectiveF.73 Fault: Water pressure sensor not con-nected or has short-circuitedInterruption/short circuit of water pressure sensor, interruption/short to earthin supply line to water pressure sensor or water pressure sensor defectiveF.74 Fault: Electrical problem in the waterpressure sensorLine to water pressure sensor has a short circuit to 5 V/24 V or internal faultin the water pressure sensorF.77 Fault: Condensate or smoke Applies to: Installed condensate pump or flue non-return flap (optional)Check the defective condensate pump or flue non-return flapF.83 Fault: Dry fire When the burner starts, the temperature change recorded by the flow orreturn temperature sensor is non-existent or too small: Insufficient water inthe product, flow or return temperature sensor incorrectly attached to thepipeF.84 Fault: Flow/return temperature sensor Values not consistent, difference between flow and return < -6 KFlow and return temperature sensors signalling implausible values: Flow andreturn temperature sensors have been inverted, flow and return temperaturesensors have not been correctly installedF.85 Fault: Temperature sensor The flow and/or return temperature sensors have been installed on the samepipe/incorrect pipeTemperature sensor not connected or is connected incorrectlyF.87 Fault: Ignition transformer cable Ignition transformer cable harness not connected to the main PCB or it isconnected incorrectly, short circuit in the cable harness or damaged ignitiontransformerF.88 Fault: Gas valve assembly Gas valve assembly not connected or it is connected incorrectly, short circuitin the cable harnessF.89 Fault: Pump Pump not connected or it is connected incorrectly, incorrect pump connec-ted, short circuit in the cable harnessErr Fault: Interface communication Interface PCB not connected or connected incorrectly, short circuit in thecable harness