BoilerFaultCodesThe 6 most common faults
01
5v[12 High DIY-safe
Your boiler's main control panel has temporarily lost its connection with the internal computer, meaning it cannot receive your commands for heating or hot water.
What to try first
Turn the boiler off completely at the fused spur switch or wall socket.Wait approximately 60 seconds to allow the internal components to fully discharge.Turn the power back on and check if the display resets and the error clears.
02
e10 High DIY-safe
Your boiler has temporarily stopped working because the water inside is not circulating properly between the heating pipes.
What to try first
Check that your heating system pressure is at the correct level, usually between 1 and 1.5 bar on the pressure gauge.Ensure your radiators and thermostatic valves are open and not blocked, allowing water to flow freely.Try resetting the boiler using the reset button or turning the power off and on again.
03
5v[0 High Engineer
Your boiler's internal memory has encountered a configuration error and needs to be reset or reprogrammed by a professional.
Full guide for 5v[004
5v[2 High Engineer
Your boiler has detected that the water inside is heating up far too quickly, which usually happens when water isn't flowing through the system properly.
Full guide for 5v[205
5v[7 High Engineer
Your boiler is temporarily shutting down because the water getting hot inside is not circulating away fast enough, causing a dangerous temperature gap.
Full guide for 5v[706
5v[10 High Engineer
Your boiler has temporarily stopped working because a safety shutdown switch has been triggered.
Full guide for 5v[10on the Main MainEco
HMI Display PCBMain PCBInternal wiring harnessCentral heating pumpFlow and return thermistorsAutomatic bypass valve
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 Main 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