Viessmann VITOTRONIC 200 Installation And Service Instructions Manual page 62

Function Description, Vitotronic 200/300-K
Heating Circuit Control Unit of the Vitotronic 300-K
Time in h
Example using the settings in the factory set condition
Legend
A Start of operation with standard room temperature
B Set boiler water or supply temperature in accordance
with the selected heating curve
C Set boiler water or supply temperature in
accordance with the selected coding address "fa":
122°F + 20% = 146°F (50°C + 20% = 60°C)
D Duration of operation with raised set boiler water or
supply temperature in accordance with coding address
"fb": 60 min.
62
Vitotronic 200, HO1B and 300-K, MW2C Installation/Service
(continued)
Control sequence
Mixing valve circuit
The mixing valve motor will not be controlled within the
"neutral zone" ±2°F (±1 K).
Supply temperature drops
[Set value -2°F (-1 K)]
The mixing valve motor receives the signal "Mixing valve
open".
The signal duration lengthens with an increasing control
differential.
The duration of pauses reduces with an increasing
control differential.
Supply temperature rises
[Set value +2°F (+1 K)]
The mixing valve motor receives the signal "Mixing valve
closed".
The signal duration lengthens with an increasing control
differential. The duration of pauses reduces with an
increasing control differential.