Your boiler is struggling to push water around your heating system, usually because too many radiators are turned off or there is a blockage in the pipes.

DIY fix possible

Ensure all radiator valves are fully open to allow water to circulate freelyCheck that your system pressure gauge is set between 1 and 1.5 barTurn the boiler off at the mains for 60 seconds and then switch it back on to reset the system