BoilerFaultCodesTechnical description
Check if 'Off' is shown on display, check CH Timer and Room Thermostat, Radiator Valves, and 230Vac at SL2 IN.
What causes this fault?
This issue occurs because the boiler is waiting for a command to start that isn't arriving, meaning the communication link between your wall controls and the boiler is interrupted. It is physically caused by a setting that is keeping the heating off, such as a timer schedule, or a lack of power reaching the boiler's heating trigger. The most common reason is simply that the room thermostat is set too low or the batteries in your controller have died.
This code is frequently seen during the first cold spell of autumn when homeowners try to turn their heating back on after it has been inactive all summer.
DIY fix possible
Check that the boiler display does not say 'Off' and ensure it is set to the 'Winter' or 'Heating and Hot Water' mode.Verify that your room thermostat is set higher than the current room temperature and has fresh batteries.Check your programmer or heating timer to ensure it is in an 'On' period and that your radiator valves are turned up.