Vaillant ecoTEC Plus Combi F.042 – The coding resistor (in the wiring harness) or the gas group resistor (on the PCB, if available) is invalid.

F.042

The coding resistor (in the wiring harness) or the gas group resistor (on the PCB, if available) is invalid.

Vaillant ecoTEC Plus Combi

Possible cause

Heat cell coding resistor is not detected

Measure

Check the coding resistor (PCB plug X25, contact 11/12).