BoilerFaultCodesThe 6 most common faults
Your boiler has shut itself down because it has detected that the water inside is getting too hot.
Check that your radiator valves are open and not turned to off.Wait 30 minutes for the boiler to cool down naturally.Press and hold the 'R' or reset button for a few seconds to restart the system.
Your boiler has detected that the water pressure in the central heating system is too low to operate safely and has switched itself off.
Locate the filling loop (the silver braided hose) underneath the boiler.Slowly open the tap or taps on the filling loop to allow water into the system.Watch the pressure gauge and close the taps once the needle reaches between 1 and 1.5 bar.
Your boiler has detected that hot water isn't moving through the system properly, which usually means it is overheating and has shut down as a safety precaution.
Check that all radiator valves (TRVs) are fully openBleed all radiators to remove trapped air from the systemCheck the boiler pressure is between 1.0 and 1.5 barReset the boiler to see if the fault clears
Your boiler has lost its flame while it was running, which means it has stopped providing heating and hot water for safety reasons.
Check if other gas appliances in your home, like a hob, are working to ensure you have a gas supplyCheck if your gas meter has credit and that the handle on the gas pipe is fully turned to the 'on' positionPress and hold the Reset button for five seconds
Your boiler has failed to ignite or stay lit, which usually means the gas isn't reaching the burner or the system can't detect a flame.
Check if other gas appliances (like a hob) are working to confirm gas supply.Check if your gas emergency control valve is open and your prepayment meter has credit.If it is freezing outside, check if the white plastic condensate pipe is frozen and thaw with warm water.Press and hold the 'R' or Reset button for five seconds.
Your boiler has switched itself off because it has detected an overheating issue to keep the system safe.
Check that your radiator valves are open and not turned to zero.Ensure your boiler pressure is between 1 and 1.5 bar on the gauge.Perform a 'Reset' by turning the selector knob to the 'R' position for five seconds.
on the Baxi 825 Combi
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 Baxi 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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
Affiliate links. We may earn a commission at no extra cost to you.