BoilerFaultCodesThe 6 most common faults
Your boiler has paused because a safety switch related to your underfloor heating has detected a problem or has been disconnected.
Check if your underfloor heating thermostat is turned down too low or is turned off.Verify that the underfloor heating pump and manifold wiring centers have power.Ensure any manual safety limit thermostats on the underfloor pipework haven't been tripped by high temperatures.
Your boiler has stopped working because the water pressure is too low for it to operate safely.
Locate the filling loop (usually a silver flexible hose) under or near the boiler.Open the one or two taps on the loop slowly until you hear water flowing.Watch the pressure gauge and close the taps once the needle reaches between 1.0 and 1.5 bar.
Your boiler has detected that the water inside is getting much too hot, so it has shut down to prevent damage.
Check that all radiator valves are fully openEnsure the boiler pressure gauge is between 1.0 and 1.5 barBleed all radiators to remove trapped airPress the reset button once the boiler has cooled down
Your boiler is trying to light but cannot detect a flame, so it has shut down for safety.
Check if other gas appliances in your home (like a hob) are working to ensure gas supply.Verify that your external gas meter has credit if you use a prepay meter.Check that the white condensate pipe leaving the boiler isn't frozen if it is winter.Try resetting the boiler using the reset button on the front panel.
Your boiler has detected that the water returning to the unit is much too hot, causing it to shut down for safety.
Check that all radiator valves are fully openEnsure the boiler pressure is between 1 and 1.5 barRestart the boiler to see if the error clears
Your boiler has stopped working because the main control board is unable to talk to or control the fan.
Full guide for 3Aon the Buderus 600-28C
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 Buderus 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