F.070
The Device Specific Number (DSN) is incorrect, missing or does not match the coding resistor.
Vaillant ecoTEC Plus Combi
Possible cause
Device Specific Number not set correctly following simultaneous replacement of the PCB and display
Measure
1. Set the correct Device Specific Number.
2. Following simultaneous replacement of the PCB and display, replace the control electrode.
Possible cause
Fault in the electrical connection for the gas valve assembly
Measure
Check the wiring harness between the PCB and gas valve assembly, including all plug connections.