BoilerFaultCodesThe 6 most common faults
Your boiler has switched itself off because the water level inside the heating system has dropped too low to operate safely.
Locate the external filling loop, which is usually a silver braided hose under the boiler.Open the small valve or tap attached to the loop slowly, allowing water to enter the system while watching the pressure gauge.Stop filling once the needle reaches the green zone, typically between 1.0 and 1.5 bar, then ensure the valve is fully closed.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
Locate the external filling loop, which is usually a flexible silver hose under the boiler connecting two pipes.Open the attached valves slowly to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly and ensure no water is leaking from the connection points.
Your boiler is trying to start up but cannot light the gas flame needed to produce heat.
Full guide for F1Your boiler has lost the ability to accurately measure the water temperature, so it has safely shut down to prevent overheating.
Full guide for F2Your boiler has detected that it is getting dangerously hot and has automatically shut itself down to prevent damage.
Full guide for OverheatYour boiler has stopped working as a safety precaution because it either failed to light or became too hot.
Full guide for Lock-outon the Heatline Capriz 28
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 Heatline 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