Your boiler is working normally but is currently set to a low heating temperature, meaning your radiators may feel cooler than usual.
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 user-adjustable heating control dial is turned to a low setting. It indicates that the system is functioning correctly but is physically restricted from getting the water hot enough to heat the house quickly. The most common reason is simply that the temperature knob on the front of the boiler has been nudged or purposefully set to a lower level.
This is often noticed in autumn when the weather first turns cold and homeowners find their radiators are not getting hot enough to warm the room.
DIY fix possible
Locate the temperature control knob or buttons on the front of the boiler panel.Turn the dial clockwise or press the 'up' button to increase the target water temperature.Wait a few minutes to see if the radiators begin to feel warmer.
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