This is a system with 2 tanks or tank groups. The first serves as a solar tank; the second, downstream, as a standby tank. This configuration is ideal if several tanks are planned for the system on account of its size or an existing standby tank is to continue being used.

A2 - Hot Water System with 2 Tanks, without Layer Charging Device

A2.1 - Hot Water System with 2 Tanks, with Layer Charging Device

A2.2 - Hot Water System with 2 Tanks, the hot water tank is directly fired (US system)

A2.3 - Hot Water System with 2 Tanks, the solar tank has an external heat exchanger, and the hot water tank is directly fired (US system)

A2.4 - Hot Water System with 2 Tanks, the solar tank has an external heat exchanger, and the hot water tank is heated by the boiler.

A2.5 - Hot Water System with 2 Tanks, external heat exchanger for the solar circuit and boiler heat exchanger

The system consists of the following components:

#	Hydraulic Connection / Components	A2	A2.1	A2.2	A2.3	A2.4	A2.5
1	External Boiler	x	x			x	x*
2	Stratification
	x
3	External Heat Exchanger				x	x	x
4	Direct Firing in HW Tank			x	x

• a: Collector Loop - x for all system types
• b: Collector Array - x for all system types
• c: Dual coil DHW tank - x for all system types
• d: DHW Consumption - x for all system types
• e: Single Coil Solar Tank (Monovalent) - x for all system types
• f: Destratification- x for all system types

*The internal heat exchanger in the boiler is not depicted.

On the System Definition > Control page, Control, 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.