BoilerFaultCodesThe 6 most common faults
Your boiler has likely sensed that it is getting too hot and has stopped firing to protect itself from damage.
Check that your radiator valves are fully open.Ensure your thermostat is calling for heat correctly.Restart the boiler by turning the selector switch to the 'Reset' position for five seconds.
Your boiler has paused because a safety switch or external control has told it to stop running, often due to an issue with the condensate pipe or a connected external device.
Check if the outdoor condensate drainage pipe is frozen or blockedThaw a frozen pipe using warm (not boiling) water or a heat packReset the boiler by turning the selector switch to 'R' for five seconds
Your boiler is struggling to keep its flame lit, causing it to shut down for safety.
Check that your gas emergency control valve is open and you have credit on your meter.Inspect the condensate pipe outside to ensuring it hasn't frozen during cold weather.Reset the boiler by turning the selector switch to the 'R' position for five seconds.
Your boiler is having trouble communicating with the thermostat or its own internal controls, preventing it from starting up correctly.
Check if your wireless thermostat has fresh batteriesEnsure the thermostat is within signal range of the boilerTurn the electrical power to the boiler off and back on to reset the connection
Your boiler has switched itself off because it has detected it is getting too hot, likely due to a circulation problem or a temporary blockage.
Check that your radiator valves are fully openEnsure your system pressure is between 1 and 1.5 bar (if a gauge is visible)Perform a manual reset by turning the selector knob to 'R' for five seconds
Your boiler has failed to light after several attempts, which means it has shut down for safety and cannot provide heating or hot water.
Check if other gas appliances, like a cooker hob, are working to ensure gas is being supplied to the property.If it is freezing outside, check if your white plastic condensate pipe is frozen and thaw it with warm water.Press and hold the reset button or turn the selector knob to 'R' for five seconds to restart the boiler.
on the Baxi 600 Heat
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.
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