BoilerFaultCodesThe 6 most common faults
01
04 High DIY-safe
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
What to try first
Locate the external filling loop, which is usually a small metal or braided hose located under the boiler.Open the small valve or tap on the loop to let water in until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve or tap tightly to stop the flow of water.
02
01 High Engineer
Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Full guide for 0103
02 High Engineer
Your boiler has stopped working because it cannot circulate water properly, often due to a pump blockage or air trapped in the system.
Full guide for 0204
06 High Engineer
Your boiler's internal computer is struggling to recognise its own settings due to an incorrect configuration of the small connection pins on its control board.
Full guide for 0605
07 High Engineer
Your boiler is struggling to read its own internal water temperature, so it has shut down to prevent overheating.
Full guide for 0706
08 High Engineer
Your boiler has detected that it is running too hot and has automatically shut down to prevent damage.
Full guide for 08on the Vokera Synergy 25 E
Filling loopPressure gaugeExpansion vesselIgnition electrodeGas valvePCB
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 Vokera 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