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Applications Manual Bosch Greenstar | 41
Bosch Thermotechnology Corp.
Data subject to change
2.8 System 8: Greenstar Heating Boiler in a
single zone system with room thermostat
and DHW tank loading
Summary:
Single boiler with primary/secondary piping confi guration
supplying one heating zone. Outdoor reset with FW200
controller mounted on the boiler. 3rd party room thermo-
stat used to communicate heat demand.
This system is identical to System 7 except that it does not
feature constant circulation. The system circulator runs
only when a heat demand is communicated by the room
thermostat and shut off when the heat demand goes away.
Use this design where Systems 1 through 4 cannot be
used due to too great a system pressure drop. Primary/
secondary piping is also required for radiant fl oor and
panel radiator applications.
Primary/secondary piping isolates the system fl ow from
the boiler fl ow and prevents the system from infl uencing
boiler performance.
This system is designed for installations with other
heat sources, e.g. wood stoves or signifi cant 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 fi red 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
temperature) according to outdoor temperature. The 3rd
party room thermostat turns the boiler on and off based
on the conditions in the living space.
FW200 provides warm weather shutdown.
For temperature sensitive radiant fl oor applications, install
a thermostatic tempering valve for overheat protection.
Required components:
Greenstar heating boiler.
FW200 controller in the room.
Primary/secondary piping and system pump.
Thermostatic mixing valve (optional - overheat
protection for temperature sensitive floors).
3rd party room thermostat ; self powered with dry
contact closure.
Indirect Fired DHW Tank.
Tank loading pump of sufficient capacity.
Additional instructions:
See manufacturer’s installation and operating instructions.