Applications Manual | Bosch Greenstar 57 |
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2.12System 12: Greenstar Heating Boiler with zone valves and room thermostats
Summary:
Single boiler with primary/secondary piping configura- tion supplying three heating zones controlled by 3rd party room thermostats with zone valves. Outdoor reset with FW200 controller mounted on the boiler.
The zone circulator runs only when a heat demand is com- municated by the room thermostats and shut off when the heat demand goes away.
Primary/secondary piping isolates the system flow from the boiler flow and prevents the system from influencing boiler performance.
This setup allows the use of a low energy ECM pump (e.g. Grundfos Alpha) that adjusts the flow rate based on back pressure depending on the number of zones calling.
This system works particularly well for installations with other heat sources, e.g. wood stoves or significant solar gain. Compared to systems with the FW200 installed in the room that will throttle down the boiler output when the room reaches its set point, in this setup the thermostat will shut the boiler off.
This system can also be used with a combi boiler (see system 6) instead of the indirect fired DHW tank.
In detail:
This system runs on pure outdoor reset without room feedback on the heating curve. The FW200 installed in the boiler adjusts the heating curve (boiler supply tempera- ture) according to outdoor temperature.
The 3rd party room thermostats turn the boiler and the zone pump on and off based on the conditions in the living space.
FW200 provides warm weather shutdown.
For temperature sensitive radiant floor applications install a thermostatic tempering valve for overheat protection.
Required components:
Greenstar heating boiler.
FW200 controller in the boiler.
Primary/secondary piping and system pump.
Thermostatic mixing valve (optional - overheat protection for temperature sensitive floors).
3rd party room thermostats with dry contact closure in each zone.
Zone valve panel (e.g. TACO ZVC403 or similar).
Zone pump (ECM recommended).
Indirect fired DHW tank.
Tank loading pump of sufficient capacity.
Additional instructions:
See manufacturer’s installation and operating instructions.
Bosch Thermotechnology Corp. | Data subject to change |