Your boiler's internal water pressure is currently too high, which can put unnecessary strain on the system's components.

DIY fix possible

Locate a radiator in your home, preferably one upstairs.Place a cloth under the radiator's bleed valve and use a radiator key to open it slightly.Let a small amount of water out until the boiler pressure gauge drops back into the green zone (usually 1.0 to 1.5 bar).Close the valve tightly and check that the boiler fault has cleared.