Viessmann VITODENS 242-F Technical Manual page 83

Control units
(cont.)
Programming unit:
■ Easy operation through:
– Plain text display with graphic ability
– Large font and black/white depiction for good contrast
– Context-sensitive help
– Removable programming unit; can be mounted as option on the
wall with separate accessory
■ With digital time switch
■ Control keys for:
– Navigation
– Confirmation
– Help
– Extended menu
■ Setting the:
– Room temperature
– Reduced room temperature
– DHW temperature
– Heating program
– Time programs for central heating, DHW heating and DHW circu-
lation
– Economy mode
– Party mode
– Holiday program
– Heating curves
– Codes
– Actuator tests
– Test mode
■ Displaying:
– Boiler water temperature
– DHW temperature
– Information
– Operating details
– Diagnostic details
– Fault messages
Functions
■ Weather-compensated control of the boiler water and/or flow tem-
perature
■ Control of one heating circuit without mixer and two heating circuits
with mixer
■ Electronic maximum and minimum temperature limit
■ Demand-dependent heating circuit pump and burner off control
■ Adjustment of a variable heating limit
■ Anti-seizing pump protection
■ Heating system frost protection
■ Integral diagnostic system
■ Maintenance display
■ Cylinder thermostat with priority
■ Control of solar DHW heating in conjunction with solar control mod-
ule SM1 (only with Vitodens 343-F)
■ Display of the solar yield (only with Vitodens 343-F)
■ 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 the heating load calculation are
met. To reduce the heat-up load, 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 period.
According to the Energy Savings Order [Germany], the temperature in
each room must be individually controlled, e.g. through thermostatic
radiator valves.
Control characteristics
PI characteristics with modulating output.
Time switch
■ Individual and 7-day program
■ Automatic summer/winter time changeover
VITODENS
■ 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 backup: 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
Heating program "w"
The burner starts only when the DHW cylinder needs to be heated up
again.
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).
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
1.4
1.2
1.0
0.8
0.6
0.4
0.2
-15 -20 -25 -30
VIESMANN
83
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