BoilerFaultCodesTechnical description
Boiler has power and selector is in ON position.
What causes this fault?
This indicator shows that the boiler is functional and waiting for a command to start heating. If your home is cold, the most common reason is that the external thermostat or timer is set too low or has failed to send a 'call for heat' signal to the unit. Essentially, the boiler is ready to work, but it hasn't been told to turn on yet.
This situation is more frequent during the first cold spell of autumn when external thermostats or timers are first adjusted after being off all summer.
DIY fix possible
Check that your room thermostat is turned up higher than the current room temperature.Ensure the heating programmer or timer is set to 'ON' or 'AUTO'.Check that the thermostatic radiator valves (TRVs) are turned open.