F.022
No/insufficient water in the product or the water pressure is too low.
Vaillant ecoTEC Plus System
Possible cause
Insufficient/no water in the product.
Measure
1. Fill the heating installation.
2. Check the product and the system for leakages.
Possible cause
Fault in the electrical connection for the water pressure sensor
Measure
Check and, if required, replace the wiring harness between the PCB and sensor, including all plug connections.
Possible cause
Cable for the pump/for the water pressure sensor is loose/not connected/defective
Measure
Check the cable for the pump/for the water pressure sensor.
Possible cause
Water pressure sensor defective
Measure
Check and, if required, replace the water pressure sensor.
Possible cause
Pump operation interrupted
Measure
Check and, if required, replace the cable to the pump/to the water pressure sensor.
Possible cause
Solenoid valve for the automatic filling device defective
Measure
Check the automatic filling device and replace it, if necessary.
Possible cause
Internal expansion vessel defective
Measure
Check and, if required, replace the internal expansion vessel.
This code also applies to: