Viessmann Vitotronic 300 Installation And Service Instructions Manual page 52

Function Description
Heating Circuit Control Unit
Example using the settings in the delivered condition
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 delivered condition
Time in hours
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 coding address "FA":
122° F (50° C) + 20% = 146° F (60° C)
D Duration of operation with raised set boiler water or
supply temperature in accordance with coding address
"FB": 60 min
52
(continued)
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.
Outside temp.
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.
Control sequence
Mixing valve circuit
The mixing valve motor will not be controlled within the
"neutral zone" (±1 K). Supply temperature drops
(Set value −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 +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.
Vitotronic 300, GW5B Installation and Service