Viessmann VITODENS 300-W Technical Manual page 80

Control units
(cont.)
■ Pump anti-seizing protection
■ Frost protection monitoring for the heating system
■ Integral diagnostic system
■ Maintenance display
■ Cylinder temperature controller with priority control
■ In conjunction with solar control module, type SM1:
– Control unit for solar DHW heating and central heating backup
– Graphic display of solar yield
■ Auxiliary function for DHW heating (short-term heating to a higher
temperature)
■ Screed drying program
■ External starting and blocking (in conjunction with extension EA1)
The requirements of DIN EN 12831 for calculating the heat load are
met. To reduce the heat-up output, the reduced room temperature will
be raised in case of low outside temperatures. The flow temperature
will be raised for a limited time to reduce the heat-up time after a set-
back phase.
According to the Energy Saving Ordinance [Germany], the tempera-
ture in each room must be individually controlled, e.g. through ther-
mostatic radiator 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 switch-
ing 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-
7
perature rises above approx. +3 °C.
Summer mode
Operating program "w"
The burner only starts when the cylinder needs reheating or when
DHW is drawn from a gas combi boiler.
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 temperature
of the heating circuits with mixer (in conjunction with the extension 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 temperature (delivered
condition 8 K).
VIESMANN
80
The flow temperature required to reach a specific room temperature
depends on the heating system and the thermal insulation of the build-
ing 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 limiter
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 -10
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
Permissible ambient temperature
– during operation
– during storage and transport
Cylinder temperature sensor (Vitodens 200-W and 300-W)
Standard delivery for:
■ Connection set for DHW cylinders below the boiler (120 or 150 litre)
(order separately)
■ Connection set for DHW cylinders adjacent to the boiler (160 to
400 litres) or alternative DHW cylinders (order separately)
Specification
Cable length
IP rating
Sensor type
Permissible ambient temperature
– during operation
– during storage and transport
Cylinder temperature sensor (Vitodens 222-W) and outlet tem-
perature sensor
These sensors are connected to the control unit and built into the boiler
or cylinder.
Specification
IP rating
Sensor type
Permissible ambient temperature
– during operation
– during storage and transport
1.4
1.2
1.0
0.8
0.6
0.4
0.2
-15 -20 -25 -30
Viessmann NTC, 10 kΩ at
25 °C
0 to +130 °C
–20 to +70 °C
3.75 m, fully wired
IP 32
Viessmann NTC 10 kΩ at
25 °C
0 to +90 °C
–20 to +70 °C
IP 32
Viessmann NTC 10 kΩ at
25 °C
0 to +90 °C
–20 to +70 °C
VITODENS