F.318
The 3-port motorised valve does not move.
Vaillant ecoTEC Plus Combi
Possible cause
Fault in the electrical connection for the 3-port diverter valve
Measure
Check the wiring harness between the PCB and 3-port diverter valve, including all plug connections.
Possible cause
3-port diverter valve defective or blocked
Measure
Check and, if required, replace the 3-port diverter valve.