Your boiler has too much water in the system, which puts unnecessary stress on the internal pipes and seals.

DIY fix possible

Check that the filling loop valves are fully closed and not letting in waterBleed water from a radiator using a bleed key to lower the system pressureMonitor the pressure gauge until it returns to the normal range (usually 1.0 to 1.5 bar)Reset the boiler once the pressure is stabilised