Viessmann VITODENS 200-W Type B2HA Technical Manual page 79

Control units
(cont.)
Functions
■ Weather-compensated control of the boiler water and/or flow tem-
perature
■ Control of one heating circuit without mixer and 2 heating circuits
with mixer
■ Electronic maximum and minimum temperature limit
■ Demand-dependent heating circuit pump and burner shutdown
control
■ Adjustment of a variable heating limit
■ Pump anti-seizing protection
■ Frost protection monitoring for the heating system
■ Integral diagnostic system
■ Service indicator
■ Cylinder temperature controller with priority control
■ In conjunction with solar control module, type SM1:
– Control of solar DHW heating and central heating backup
– Graphic representation of the solar energy yield
■ Auxiliary function for DHW heating (short term heating to a higher
temperature)
■ Screed drying program
■ External starting and blocking (in conjunction with EA1 extension)
■ Connection of the circulation pump for cylinder heating on the
main PCB
To reduce the heat-up output, the reduced room temperature is
raised when outside temperatures are low. To shorten the heat-up
time after a setback phase the flow temperature is raised for a limi-
ted time.
According to the German Energy Saving Ordinance, the temperature
in each room must be individually controlled, e.g. by means of ther-
mostatic valves.
Control characteristics
PI characteristics with modulating output.
Time switch
Digital time switch (integrated into the programming unit)
■ Individual day and seven-day program
■ Automatic summer/wintertime changeover
■ Automatic function for DHW heating and DHW circulation pump
■ Time, day and standard switching times for central heating, DHW
heating and the DHW circulation pump are factory-set
■ Switching times are individually programmable, i.e. up to four
switching periods per day
Shortest switching interval: 10 minutes
Power reserve: 14 days
Setting the operating programs
The heating system frost protection (see frost protection function)
applies to all heating programs.
The following heating programs can be selected:
■ Heating and DHW
■ Only DHW
■ Standby mode
External heating program changeover in conjunction with EA1 exten-
sion.
Frost protection function
■ The frost protection function will be started when the outside tem-
perature drops below approx. +1 °C.
With frost protection, the heating circuit pump is switched ON and
the boiler water is maintained at a lower temperature of approx.
20 °C.
The DHW cylinder will be heated to approx. 20°C.
■ The frost protection function will be stopped when the outside tem-
perature rises above approx. +3 °C.
Summer mode
Operating program "w"
The burner starts only when the DHW cylinder needs to be heated
up.
VITODENS 200-W
Adjusting the heating curves (slope and level)
The Vitotronic 200 controls the boiler water temperature (= flow tem-
perature of the heating circuit without mixer) and the flow tempera-
ture of the heating circuits with mixer (in conjunction with the exten-
sion kit for one heating circuit with mixer) in weather-compensated
mode. The boiler water temperature is automatically boosted by
between 0 and 40 K higher than the currently required set flow tem-
perature (delivered condition 8 K).
The flow temperature required to reach a specific room temperature
depends on the heating system and the thermal insulation of the
building to be heated.
Adjusting the heating curves matches the boiler water temperature
and the flow temperature to these operating conditions.
Heating curves:
The upper boiler water temperature is limited by the temperature lim-
iter and the temperature set at the electronic maximum thermostat.
The flow temperature cannot exceed the boiler water temperature.
Heating curve slope
90
80
70
60
50
40
30
20
20 15 10 5 0 -5
Outside temperature in °C
Heating systems with low loss header
When using hydraulic separation (low loss header), connect a tem-
perature sensor for use in the low loss header.
Boiler water temperature sensor
The boiler water temperature sensor is connected to the control unit
and built into the boiler.
Specification
Sensor type Viessmann NTC 10 kΩ at 25 °C
Permissible ambient temperature
– Operation 0 to +130 °C
– Storage and transport –20 to +70 °C
Cylinder temperature sensor
The standard delivery includes the DHW cylinder connection set.
Specification
Lead length
IP rating
Sensor type
Permissible ambient temperature
– During operation
– During storage and transport
Outside temperature sensor
Installation site:
■ North or north-west facing wall of the building
■ 2 to 2.5 m above the ground, for multi storey buildings in the upper
half of the second floor
1.4
1.2
1.0
0.8
0.6
0.4
0.2
-10 -15 -20 -25 -30
3.75 m, fully wired
IP 32
Viessmann NTC 10 kΩ at
25 °C
0 to +90 °C
–20 to +70 °C
VIESMANN
5
79