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F.047

The signal for the domestic hot water temperature sensor at the output for the internal cylinder is implausible.

Vaillant ecoTEC Plus System

Possible cause
Fault in the electronic connection for the cylinder outlet temperature sensor
Measure
Check the wiring harness between the PCB and sensor, including all plug connections.
Possible cause
Cylinder outlet temperature sensor defective
Measure
Replace the cylinder outlet temperature sensor.
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