Technical description
summer mode
What causes this fault?
This status occurs because the central heating function has been manually switched off, leaving only the hot water operational. It is usually caused by the user or an engineer adjusting the control dial or digital settings to a 'hot water only' position. There is no actual mechanical fault with the boiler; it is simply following the instruction to ignore calls for heating.
This is most common during the spring and summer months when homeowners intentionally deactivate their heating to save energy.
DIY fix possible
Locate the temperature control knob or buttons for the central heating on the control panel.Increase the heating temperature setting or turn the dial clockwise to exit summer mode.Ensure your room thermostat or programmer is also calling for heat.