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

DIY fix possible

Locate a radiator in your home that is easy to access.Open the radiator bleed valve slowly with a key until water begins to drip out.Allow a small amount of water to drain into a bowl until the boiler's pressure gauge drops back into the green zone (usually 1.0 to 1.5 bar), then tightly close the valve.