BoilerFaultCodesTechnical description
Control Status: Blocking Error (Failure to carry out a step or malfunctioning component)
What causes this fault?
This fault occurs when the boiler's internal sensors detect a reading that is slightly outside of the normal operating range, leading the system to pause for safety. This is most commonly caused by a drop in system water pressure or a temperature sensor that is beginning to provide inconsistent data to the control board.
This issue is more frequent in autumn when the heating is turned on for the first time after summer, as stagnant water and settled debris can affect sensor accuracy.
DIY fix possible
Check the central heating pressure gauge is between 1.0 and 1.5 barTurn the power switch to the boiler off and back on again after 30 secondsCheck that all radiator valves are open and not blocked