BoilerFaultCodesTechnical description
Control stop: measured flow temperature (t1) is higher than the flow temperature set (T flow set).
What causes this fault?
This fault occurs when the water inside the boiler heats up much faster than it can be moved away into your radiators or hot water cylinder. The most common reasons are a pump that is struggling to circulate the water, a blockage in the pipework, or a sensor that is sending an incorrect temperature reading to the main control board.
This issue is more frequent in autumn when heating systems are switched back on after a long summer break, as internal pump parts can seize during periods of inactivity.
DIY fix possible
Check that all radiator valves are fully open to allow water to flow.Ensure the central heating system pressure is between 1.0 and 1.5 bar.Restart the boiler using the reset button to see if the fault clears.