Technical description
Heating system part load
What causes this fault?
This occurs when the boiler has been manually or automatically adjusted to limit its maximum heat output to prevent wasting energy. It happens because your home doesn't require the boiler's full power to reach the desired temperature, so the system scales back to a more efficient level. This is a normal operational setting rather than a component failure.
You may see this more often during milder weather when your home requires very little heat to stay comfortable compared to the depths of winter.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.