Technical data

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5693 973 - 05
Vitotronic 300, GW5B & MW1B Installation and Service
Heating Circuit Control Unit of the Vitotronic 300-K (continued)
Differential temperature:
The differential temperature is adjustable via coding
address “9F” in the “General” group, factory set condition
8 K.
The differential temperature is the value by which the
common supply temperature should be higher than the
highest currently required supply temperature of the
heating circuit with mixing valve.
H System with only one heating circuit with mixing valve:
The common set supply temperature is regulated
automatically to 8 K above the set supply temperature
of the heating circuit with mixing valve.
H System with system circuit and heating circuits with
mixing valve:
The common set supply temperature operates in
accordance with its own heating curve. The differential
temperature of 8 K towards the set supply temperature
of the heating circuits with mixing valve is set at the
factory.
Raising the reduced room temperature
During operation with reduced room temperature, the
reduced set room temperature can be automatically raised
subject to the outside temperature. The temperature is
raised in accordance with the selected heating curve, but
no higher than the set standard room temperature.
The outside temperature limits for the start and end of the
temperature raising can be adjusted via coding addresses
“F8” and “F9” in the “Heating circuit...” group.
Function Description
Legend
A Maximum supply temperature limit (coding address
“37” in the “Cascade” group)
B Slope = 1.8 for system circuit
C Slope = 1.2 for heating circuit with mixing valve
D Common supply temperature (at a differential
temperature = 8 K)
E Lower common supply temperature
Supply temperature control
Reducing the heat-up time
During the transition from operation with reduced room
temperature to operation with standard room temperature,
the boiler water or supply temperature will be raised in
accordance with the selected heating curve. The boiler
water or supply temperature increase can be automatically
raised.
The value and duration of the additional increase of the
set boiler water or supply temperature can be adjusted in
coding addresses “FA” and “FB” in the “Heating circuit...”
group.
Legend
A Heating curve for operation with standard room
temperature
B Heating curve for operation with reduced room
temperature
Example using the settings in the factory set condition
Boiler water or Supply temperature
Outside temp.
Set room temperature
Outside temperature
Supply temperature