Bosch Appliances 100 Combi Boiler manual Summary

2.4System 4: Greenstar Heating Boiler in a single zone system with solar thermal DHW and boiler backup

Summary:

Single boiler supplying one baseboard heating zone equipped with FW200 outdoor reset controller with built- in room sensor in the living space . This system is using the boiler pump for zone water circulation and DHW tank loading. A diverter valve is used to switch between space heating and tank loading. This system is identical to Sys- tem 3 with an added solar thermal DHW heating system.

This design can only be used with a single loop baseboard system that has a low pressure drop. Radiant floors, panel radiator, or multi zone systems require primary-secondary piping. Do not install zone valves with this system.

Max. 70' (21 m) of 3/4" baseboard at a 20°F delta T and a flow rate of 4.0 gpm plus the necessary supply and return piping.

Ensure to select a solar tank with a boiler coil pressure drop that does not exceed the capacity of the boiler pump (see pages 11 & 12 for details).

Solar thermal provides renewable energy to heat DHW year round, and if sized properly reduce energy consumption significantly. Bosch offers plug and play components

that are designed to work together with a boiler backup system. Bosch solar thermal systems are qualified for government and utility incentives reducing the upfront investment cost significantly. Bosch solar thermal collectors work even in the winter and under cloudy skies preheating water, and reducing boiler run time and burner starts.

In detail:

The FW200 is an outdoor temperature based controller with room temperature influence. The controller adjusts the heating curve (boiler supply temperature) according to outdoor temperature. When the FW200 is wall mounted, it also uses room temperature to adjust the heating curve and modify boiler supply temperature.

FW200 provides warm weather shutdown.

The control of the solar thermal system is integrated with the FW200 boiler control, and reduces boiler run time and burner starts significantly compared to independent sys- tems. The solar pump will run whenever the collectors are 16°F (9°C) warmer than the bottom of the solar tank.

It is recommended to double the volume of the solar thermal DHW tank compared to an equivalent conventional indirect fired DHW tank. This allows sufficient backup volume ("comfort zone") maintained by the boiler without sacrificing capacity for solar harvesting.

Required components:

Greenstar combi-boiler.

FW200 controller in the room.

ISM2.

DHW solar tank with 2 coils.

Bosch solar thermal system complete.

Diverter valve 120VAC, 3-way, spring return.

Additional instructions:

See manufacturer’s installation and operating instructions.

The Bosch Greenstar boiler and ISM2 offer many different solar thermal applications including space heating sup- port and pool heating. Please consult the installation and operating instructions for details.