BoilerFaultCodesThe 6 most common faults
Your boiler has detected that there is either not enough water inside the system or that the pump responsible for moving water around is not working properly.
Check the system pressure gauge on the front of the boiler to ensure it is between 1.0 and 1.5 bar.If the pressure is below 1.0 bar, use the silver filling loop located under the boiler to top up the water pressure.Once the pressure is in the correct range, turn the boiler off at the fused spur for 30 seconds and switch it back on to reset the fault.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the filling loop, which is a silver braided hose with one or two valves underneath your boilerSlowly open the valves until you hear water flowing and the pressure gauge on the front of the boiler reaches between 1.0 and 1.5 barClose the valves tightly and turn the boiler off and on again to clear the fault
Your boiler has stopped working because it can no longer accurately read the temperature of the water flowing through the heating system.
Full guide for F.00Your boiler has stopped working because it cannot accurately measure the temperature of the water returning to it, likely due to a loose wire or a faulty sensor.
Full guide for F.01Your boiler has detected an electrical fault with the sensor that measures the temperature of the water flowing to your radiators, meaning it has shut down as a precaution to prevent overheating.
Full guide for F.10Your boiler has detected an electrical fault with the sensor that monitors the temperature of the water returning from your radiators, meaning it has safely shut down to prevent potential overheating.
Full guide for F.11on the Vaillant Turbomax Plus
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Vaillant shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue