BoilerFaultCodesTechnical description
No heat demand summer operating mode
What causes this fault?
This occurs because the 'Summer Mode' setting has been activated on your boiler, which tells the system to only heat your tap water and skip the radiators. It is usually caused by a manual setting change or a smart thermostat transition intended to save energy during warmer months. The boiler is performing exactly as instructed, so it isn't broken; it is simply prioritising hot water over heating.
This status is most frequently seen in spring and summer when homeowners intentionally deactivate their heating to reduce energy bills.
DIY fix possible
Locate the radiator temperature dial or button on the boiler control panel.Turn the dial clockwise or adjust the setting to increase the target heating temperature.Ensure your wall thermostat or heating programmer is also set to 'On' or a high temperature.