The average lifespan of a central heating boiler and radiators is rated from 10 to 15 years and if your system is showing its age after that maybe time to think about replacing it in its totality. https://pipewiki.org/wiki/index.php/When_The_Scorching_Summer_Warm_Gets_Here_The_Last_Thing_You_Desire_Is_For_Your_Cooling_And_Heating_System_To_Damage_Down_On_You.