Your boiler is struggling to maintain its lowest flame setting, which is preventing it from running safely and efficiently.

Minimum regulation current reached – try resetting the boiler – checking the gas pressure and checking the combustion values and CO2 calibration – the board or valve might need replacing.

What causes this fault?

This fault occurs when the boiler's internal computer is unable to stabilize the flame at its lowest power setting, often due to an incorrect mix of gas and air. The most common reason is a drifting gas valve or a worn ignition electrode that can no longer accurately detect the small flame needed for low-demand heating. If the electronic control board cannot safely regulate this flow, it shuts the system down to prevent internal damage.