BoilerFaultCodesWhat the manual says
Manufacturer manualMax. target value for heating-system flow temperature
What causes this fault?
This fault occurs when the water leaving the boiler exceeds the maximum temperature limit set in the internal software. It is usually caused by a lack of water circulation, often because radiator valves are closed or the pump is struggling to move heat away from the heat exchanger quickly enough.
This issue often appears during the first cold spell of autumn when heating is turned back on after months of disuse, potentially revealing a seized pump or stuck radiator valves.
DIY fix possible
Check that at least two or three radiators are turned fully open (valves turned anti-clockwise).Ensure your magnetic system filter is clean and not blocked.Restart the boiler to clear the advisory status.
Avoid the next call-out bill
A cover plan would handle faults like d.71: no call-out fees, no surprise bills.
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