Vaillant F.83 fault code: what it means

Likely causes

• Low pressure or air in the system
• Sensor not fitted properly on the pipe
• Poor circulation

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
• Bleed any radiators that are cold at the top, then check the pressure again
• Reset the boiler once

What our engineer does

We vent the boiler, check the pump and sensors and confirm water is circulating properly. 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.

Other Vaillant codes

• F.00
• F.01
• F.20
• F.22
• F.23
• F.24
• F.25
• F.26
• F.27
• F.28
• F.29
• F.32
• All fault 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.