Like all good ideas, the concept is as simple as it's effective and like all good ideas that work really well, it's also stood the test of time.

The Tank-in-Tank is a DHW tank entirely immersed within an outer tank which contains the primary fluid, with the inner tank itself being a stainless steel heat exchanger. The corrugated wall of the inner tank forms a large heat exchange surface that can heat the domestic water in a very short time. It also provides a uniform temperature throughout the volume of the tank. Since the inner tank can move freely, it can expand and contract under changes in pressure and prevent limescale forming on the surface.

This simple and highly effective design allows specifiers and installers to benefit from the cost advantages of ACV's high volume production while taking comfort from the fact that the system they are specifying or installing is the best there is.

The difference is clear - in an ACV tank the primary fluid heats the domestic hot water from the outside in, whilst the others heat it from the inside out.

• A specially designed stainless steel hot water cylinder enclosed within an outer tank which is heated by the boiler
• The inner tank also acts as a large thermal store, and is surrounded by primary hot water
  • recovery is exceptionally fast because the heat transfer surface is so large
• The internal cylinder is designed to operate at up to 10 bar - suitable for any kind of application, mains pressure or vented

Sides of the cylinder are corrugated increases heat transfer area expansion and contraction in use shrugs off scale deposits Each draw-off causes natural turbulence keeps particles in suspension, so no inspection port needed

Stainless steel construction means no more anode protection (and maintenance) no more contamination, leaking and sludging caused by cracked glass linings water is held at consistently higher temperatures discourages growth of Legionellae bacteria

ACV is pleased to present a wide range of combined boilers and water heaters, hot water storage tanks and boilers suitable for domestic, commercial and industrial applications - capable of meeting even the most demanding needs.