BoilerFaultCodesTechnical description
Not heating demand form low voltage
What causes this fault?
This code appears when the boiler is powered on and ready to work but has not received a command from your room thermostat or programmer to start heating. It usually indicates that the target temperature in your home has already been reached or that there is a communication break between your controls and the boiler. Common culprits include dead batteries in a wireless thermostat or a loose connection in the external wiring.
This is frequently seen during the transition into autumn when homeowners first turn their heating back on only to find their thermostat batteries have drained over the summer.
DIY fix possible
Check that your room thermostat is turned up higher than the current room temperature.Ensure your heating programmer or central heating timer is set to 'On' or 'Auto'.Replace the batteries in your wireless wall thermostat if the screen is blank or showing a low battery icon.