Type D: Heat accumulator - vented or unvented

A heat accumulator functions in much the same way as the multicoil hot water tank (see installation type C). Heat accumulators tend to be quite big as they rely on the mass of water to store heat - the advantage is that heat from your stove can be stored up for use later on. You can often specify the amount of tapping points and coils fitted to a heat accumulator which makes them well suited to heating systems with multiple heat sources - for example you might connect a boiler stove, solar panels, and a gas boiler.

In this diagram the boiler stove is connected to the hot accumulator tank (red loop) as well as a conventional boiler shown in the bathroom (in yellow). A solar panel is also connected to the heat accumulator (in grey).
Hot water for heating comes from the tank and is shown in orange, and domestic hot water is shown as a purple line.
The steam vent pipe is shown in green and the cold water feed to the system in blue.

You can read more about heat accumulators here but on this page we will now look at a simple diagram of a typical installation linking a boiler stove, solar panels, and conventional boiler to a heat accumulator.

Please remember that this diagram is for illustration only - the actual pipe layout would be different and might include other elements such as a heat loss radiator, cold water tank and pumps.