BoilerFaultCodesThe 3 most common faults
01
F.22 High DIY-safe
Your boiler has detected that there is not enough water pressure in the system to operate safely, causing it to shut down.
What to try first
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the one or two taps on the hose until you hear water entering.Watch the pressure gauge and close the taps once the needle reaches between 1.0 and 1.5 bar.
02
F.28 High DIY-safe
Your boiler is failing to light the gas flame despite several attempts, meaning it cannot provide heating or hot water.
What to try first
Check if other gas appliances in your home, such as a hob, are working to ensure gas supply is active.Verify that your gas meter has credit and that the emergency control valve is open.Press the Reset button (indicated by a flame with a line through it) for 3 seconds to restart the ignition process.
03
F.xx High Engineer
Your boiler has encountered a technical communication or internal sensor error that prevents it from firing up correctly.
Full guide for F.xxon the Heatline Capriz 2
Filling loop tapsExpansion vesselPressure sensorIgnition ElectrodeGas ValveSpark Leads
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