BoilerFaultCodesTechnical description
No heating demand from external controls (clamp 3-4 open)
What causes this fault?
This status occurs when the boiler is waiting for a signal from your thermostat to tell it to turn on. It physically means the electrical circuit between your heating controls and the boiler is open, indicating that your home has already reached the desired temperature. The most common reasons are simply that the thermostat is turned down, the timer is set to 'off', or the thermostat batteries have run out.
This is more frequently queried in autumn when homeowners first turn their heating on and find the boiler doesn't respond because of a programmed schedule or depleted thermostat batteries.
DIY fix possible
Check if your room thermostat is turned up higher than the current room temperature.Ensure your heating programmer or timer is set to 'ON' or 'AUTO'.Replace the batteries in your wireless room thermostat if the screen is blank or showing a low battery symbol.