The Solar indirect external stainless steel unvented cylinder, has two coils the bottom coil for the solar and the top coil for boiler auxiliary heat input with twin immersions as back up. It still gives you the same Megaflow performance of high pressure hot water when used in conjunction with a heat source and attached to the mains pressure cold water to give mains pressure showering and fast filling bath, with the added benefit of lower running costs (can be as much as 60% less than traditional systems). The ACV Smartline uses the "Tank in Tank" Technology which means there are extra connection to the bottom of the outer tank for the solar to connect ot the cylinder and have one immersion.

Designed for use with a wide range of solar systems they are environmentally friendly and an efficient way of providing domestic hot water by using specifically designed coils in the base of the cylinder which gives maximum heat input and efficiency from the solar energy. They are available in different versions Thermsaver Solar Vertical, horizontal, twin coil, ACV Smartline and Smartline Multi Energy.