Viessmann Vitotronic 200 Installation And Service Instructions For Contractors page 111

Control of the heating circuits
Brief description
The control unit comprises control circuits for heating
■
circuit 1 without mixer and heating circuits 2 and 3,
each with mixer.
■ The set flow temperature of each heating circuit is
determined from the following parameters:
– Outside temperature
Set room temperature
–
Operating mode
–
– Heating curve slope and level
Functions
The heating circuit without mixer is subject to the boiler
water temperature and its control range limits.
The heating circuit pump is the only actuator.
The flow temperature of the heating circuits with mixer
is captured by the flow temperature sensor of the rele-
vant heating circuit.
■ Upper control limit:
Electronic maximum flow temperature limit
Parameter "19" in the "Heating circuit..." group.
Lower control range limit:
■
Electronic minimum flow temperature limit
Parameter "18" in the "Heating circuit..." group.
Time program
The control unit switches over according to the time
program. In the "Heating and DHW" operating pro-
gram, the control unit switches between "Central heat-
ing with standard room temperature" and "Central
heating with reduced room temperature".
Every operating mode has its own set level.
4 time phases per day can be selected.
Outside temperature
A heating curve must be set for matching the control
unit to the building and the heating system.
The heating curve characteristics determine the set
boiler water temperature subject to outside tempera-
ture. The control unit regulates in line with an average
outside temperature. This is composed of the actual
and the adjusted outside temperature.
Room temperature
Room temperature in conjunction with a remote
control and room temperature hook-up (parameter
"0A" in the "Heating circuit...") group
Compared with the outside temperature, the room tem-
perature has a greater influence on the set boiler water
temperature (changed at parameter "0C" in the "Heat-
ing circuit..." group).
The flow temperature of the heating circuit without
■
mixer is equal to the boiler water temperature.
■ The flow temperature of the heating circuits with
mixer is regulated by the stepped opening or closing
of the mixers.
The mixer motor control changes the actuating and
pause times subject to the control differential (control
deviation).
Room temperature in conjunction with heating cir-
cuits with mixers
For control differentials (actual value deviation) > 2 K
room temperature, the room temperature influence can
be increased (parameter "0F" in the "Heating cir-
cuit..." group):
■ Quick heat-up
The set room temperature must be raised by at least
2 K by the following measures:
Enabling comfort mode
–
Changing from central heating with reduced tem-
–
perature to central heating with standard tempera-
ture
– Start optimisation (parameter "10" in the "Heating
circuit..." group)
Quick heat-up will stop when the set room tempera-
ture has been reached.
Quick setback
■
The set room temperature must be reduced by at
least 2 K by the following measures:
– Activating economy mode
– Changing from central heating with standard tem-
perature to central heating with reduced tempera-
ture
– Shutdown time optimisation (parameter "13" in the
"Heating circuit..." group)
Quick setback ends when the set room temperature
has been reached.
Function description
111