System 2: Greenstar Combi Boiler In A Single Zone System - Bosch Greenstar 57 Manual

Applications Manual
2.2 System 2: Greenstar Combi Boiler in a
single zone system
Summary:
Single combi-boiler supplying one baseboard heating
zone equipped with FW200 outdoor reset controller with
built-in room sensor in the living space. DHW generation
directly off the boiler through the tankless heat exchanger.
This system is using the boiler pump for zone water circu-
lation.
The "combi" or combination boiler is a high effi ciency
central heating boiler and water heater combined within
one compact unit. Water is heated on demand directly
from the water main eliminating the need for a hot water
storage tank.
This design can only be used with a single loop baseboard
system that has a low pressure drop. Radiant fl oors, panel
radiator, or multi zone systems require primary-secondary
piping. Do not install zone valves with this system.
The pump will run in constant circulation while in space
heating mode except during a call for DHW or when in
warm weather shutdown.
Max. 70' (21 m) of 3/4" baseboard at a 20°F delta T and a
fl ow rate of 4.0 gpm plus the necessary supply and return
piping..
In detail:
The FW200 is an outdoor temperature based controller
with room temperature infl uence. 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.
Required components:
Greenstar combi-boiler.

FW200 controller in the room.

Bosch Thermotechnology Corp.
Additional instructions:
See manufacturer's installation and operating instructions.
Install an adequately sized Pressure Relief Valve (PRV) on
the DHW outlet of the combi boiler.
To reduce the risk of scalding it is recommended to install
a DHW tempering valve.
The Greenstar combi boiler is equipped with an inter-
nal 3.17 gal (12 liter) expansion vessel. The installation
manual provides information on how to determine if it is
of suffi cient capacity for the application or if an additional
expansion vessel is needed.
Bosch Greenstar | 17
Data subject to change