F.049
The eBUS has short-circuited or two active eBUS sources have inverted polarity.
Vaillant ecoTEC Plus Combi
Possible cause
Short circuit in the eBUS connection
Measure
Check all eBUS connections.
Possible cause
Different polarities at the eBUS connection
Measure
Check the polarity (±) of the eBUS connections.
Possible cause
PCB defective
Measure
Replace the PCB.
This code also applies to: