Viessmann VITOTRONIC 100 GC1 Installation And Service Instructions Manual page 12

Heating system types
Circuit Diagram 3
Possible applications
Heating systems with manifold
arranged close to the boiler. The boiler
water supply is required to be reduced.
IMPORTANT
This circuit diagram represents a
recommendation only. It is the
responsibility of the customer and/or
heating contractor to check that this
recommendation is complete and fully
functional. Three-phase equipment
must be connected via additional
power contactors.
Available system accessories
Flue gas temperature sensor
Coding of Change required
system type
00: 1
02: 1 Set coding "02: 2" for operation with
modulating burner
03: 0 Set coding "03: 1" for oil-fired operation
(re-setting is not possible)
4A: 0
4b: 0
12
(continued)
When the return temperature falls
below the required minimum value,
the temperature sensor T2 switches
on the shunt pump. If the minimum
return temperature is not reached
despite raising the return temperature,
the supply must be reduced by at
least 50% via the temperature
sensor T1.
The shunt pump must be sized so
that bypassed water accounts for
approx. 30% of the total supply rate
of the boiler.
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Temperature sensor T1
Wiring of the temperature sensor T1
in heating systems with heating
circuit control units which are not
connected via the LON BUS to the
boiler control unit.
Coding required: "4C: 2" – use plug
sÖ for closing the mixing valves of
the heating circuits connected
downstream.
sÖ A1 Close mixing valves
A
Contactor relay, field supplied
B
Heating circuit controls
connected downstream
Switch contact closed: signal
for "close mixing valve".
Automatic change
With DHW tank:
Coding is automatically changed to "00: 2"
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Connection of the temperature sensor T1 at
plug aJA;
Coding is automatically changed to "4A: 1"
Connection of the temperature sensor T2 at
plug aJB;
Coding is automatically changed to "4b: 1"