The 2 tank system is expanded by a buffer tank for space heating. The boiler maintains the upper areas of both the DHW standby tank and the heating buffer tank at the required desired temperature.

On the System Definition > Control page, you can schedule destratification for the event that the solar tank has a higher temperature than the standby tank. The pump is switched on and off by the temperature difference between the solar tank and the standby tank.

In addition, an anti-Legionnaire’s switch can be used to briefly heat the tank group. A fixed time period on one or more days of the week is defined for this. The priority of the DHW circuit over the auxiliary heating is preset when selecting an A4 system.

A4 - Two-Tank Systems with Heating Buffer Storage, without Layer Charging Device

A4.1 - Two-Tank Systems with Heating Buffer Storage, with Layer Charging Device

#	Hydraulic Connections / Components	A4	A4.1
1	Auxiliary Heating	x	x
2	Stratification		x
3	Single coil DHW tank	x
4	Heating buffer tank	x	x
	Same Components
a	Collector Loop	x	x
b	Collector Array	x	x
c	Dual coil DHW tank	x	x
d	DHW Consumption	x	x
e	Heating Loop	x	x