Questions? comments? suggestions? issues? And finally, don’t forget to consider what you are. The combi boiler is connected to your mains water supply and heats the water directly so when you turn on a hot tap or switch your heating on, the water flows through the boiler and heats its built in heating element this means you have no need to store hot water, as it’s there when you need it! Vesta.ds,inc only request and use information.