Likely causes
- Sensor plug or wiring fault
- Faulty water pressure sensor
- Sensor blocked with sludge
What you can safely check
- Check the pressure gauge or display and top up to between 1 and 1.5 bar if it is low, then close the filling loop fully
- Reset the boiler once; if the code comes straight back, call us
What our engineer does
We test the pressure sensor and its wiring and replace the sensor if it has failed. Anything involving the gas supply, gas valve, combustion chamber, flue, fan, PCB or heat exchanger must be left to a Gas Safe registered engineer and must not be attempted by the householder.
Models this applies to: Vaillant ecoTEC plus, Vaillant ecoTEC pro, Vaillant ecoTEC exclusive, Vaillant ecoFIT pure.
Boiler repairs from £90
Diagnosis and a fixed price before the repair. Most faults fixed on the first visit. Gas Safe 925538.
Other Vaillant codes
Guidance only. Fault codes vary by model and firmware; anything involving gas, the flue, the fan, the gas valve, the PCB or the heat exchanger must be done by a Gas Safe registered engineer.
