BoilerFaultCodesThe 6 most common faults
Your boiler has detected that there is not enough water inside the system to operate safely, or the internal pump is struggling to move the water around.
Why it happens: This fault occurs when the internal sensors detect that water isn't moving through the heat exchanger as it should, leading to a risk of overheating. The most common reasons are a pump that has seized or failed, a loss of system pressure, or a physical blockage like an air lock preventing flow.
Check your system pressure gauge; if it is below 1 bar, top up the water using your boiler's filling loop until it reads between 1 and 1.5 bar.Ensure all radiator valves and your isolation valves underneath the boiler are fully open.Turn the boiler off at the fused spur for 30 seconds, then switch it back on to reset the fault.
Your boiler has tried to light itself several times but has failed, likely because there is no gas supply or the ignition part is dirty or broken.
Why it happens: This fault occurs when the boiler is unable to detect a flame after several attempts to start up. The most common reason is a lack of gas reaching the burner, often caused by a closed valve, an issue with the gas meter, or a buildup of carbon on the part that creates the spark.
Check if other gas appliances in your home, like a hob, are working to ensure gas is reaching the property.If you have a prepayment meter, check that you have remaining credit and the valve is open.Press the Reset button on the boiler control panel for one to two seconds.
Your boiler has tried to start up but cannot light the gas to create a flame.
Why it happens: This fault occurs when the boiler's control system attempts to start the combustion process but fails to detect a flame after several attempts. It is usually caused by a lack of gas supply, a worn-out ignition spark electrode that can no longer create a spark, or a faulty gas valve that isn't opening correctly.
Check that your gas supply is turned on at the meter.If you have a prepaid gas meter, check that you have remaining credit.Press the Reset button for two seconds to see if the boiler restarts.
Your boiler has failed to light the flame needed to produce heat or hot water.
Why it happens: This fault occurs when the boiler's internal sensors detect that the water coming back from your radiators is hotter than the water being sent out, which is physically impossible under normal conditions. The most common reason is that one of the temperature sensors has failed or is sending the wrong information to the control board. It can also happen if the pump is moving water in the wrong direction or if there is a significant blockage in the system's pipework.
Full guide for é2Your boiler has temporarily stopped working because a safety device wired into the system, such as a room thermostat or external timer, is signaling that something needs attention.
Full guide for 9Your boiler has detected that the internal fan responsible for venting exhaust gases safely is either not spinning or communicating properly, so it has shut down to keep your home safe.
Full guide for é8on the Remeha Avanta Plus 18s System
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 Remeha 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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