BoilerFaultCodesTechnical description
No boiler demand
What causes this fault?
This occurs when the boiler is powered on and functioning correctly but is waiting for a 'call for heat' from your heating controls. The most common reason is that your room thermostat is set lower than the current room temperature, or your external timer is currently in an 'off' period. If your controls are turned up and the light remains off, it usually indicates a communication failure or a flat battery in your wireless thermostat.
This is frequently reported during the first cold spell of autumn when homeowners forget to turn their wall thermostats up or replace the batteries in their wireless controllers.
DIY fix possible
Check that your room thermostat is turned up higher than the current room temperature.Ensure your programmer or heating timer is set to 'ON' or 'Auto'.Replace the batteries in your wireless wall thermostat if the screen is blank.