Indirect Open Vented Hot water storage cylinders Single coil indirect cylinders are used when there is one indirect heat source.Twin coil indirect cylinders are utilised when there are two indirect heat sources, for example heat inputs from a solar thermal system and a gas boiler.The heat sources may also be open vented or sealed depending on the installation.Fortic cylinders are a very compact design for an open vented cylinder. The cold water storage tank forms part of unit and sits on top of the cylinder as a single unit.Select Option Single Coil or Twin Coil |