Like combi boilers, system boilers are sealed systems, but they store hot water in a cylinder. Editing by jason szep and howard goller). We install both residential and commercial sprinkler systems to ensure your building is properly protected from fire damage. Further benefits of a combi boiler includes hot water being delivered through your taps or shower at mains pressure so you can enjoy powerful showering without the need for a pump. Quick, reliable and top quality service.