Your boiler is working normally but the temperature control is currently set to a very low heat setting.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Boiler operating, low flow temperature selected.
What causes this fault?
This code appears when the temperature control knob on the front of the boiler is turned down to its lowest point. It indicates that while the boiler is functioning correctly, it is only heating the water to a very low temperature which may not feel warm enough for your radiators. This is usually caused by someone accidentally knocking the dial or intentionally turning it down during milder weather.
This is more common during the transition from summer to autumn when homeowners begin to use their heating again but have left the controls on a low summer setting.
DIY fix possible
Locate the temperature control knob on the front of the boilerTurn the knob clockwise to increase the flow temperatureCheck if the radiators begin to feel warmer
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