Viessmann VITOCROSSAL 200 Type CM2 Technical Manual page 65

Control units
(cont.)
■ Functions via external contacts:
– External operating program changeover/External mixer open
– External blocking/External mixer closed
– External demand with set minimum boiler water temperature
– External burner blocking
■ Additional functions by means of the EA1 extension (accessories):
– External demand through default set boiler water temperature via
0 to 10 V input
– Switching a feed pump to a substation
or
Signalling of reduced mode (reduction of the heating circuit pump
speed) via a potential-free output
– 3 digital inputs for the following functions:
External operating program changeover, separate for heating cir-
cuits 1 to 3
External blocking with fault message input
Fault message input
Brief operation of the DHW circulation pump
■ Additional functions via AM1 extension (accessories, part no. 7452
092):
– Control of up to two circulation pumps, if output sÖ is already
assigned at the control unit:
Circulation pump for neutralising system
Heating circuit pump
The requirements of EN 12831 for calculating the heat load are met.
To reduce the heat-up load, the reduced room temperature will be
raised in the 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 [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 three-point output when using a modulating
burner
■ Setting range for heating curves:
– Slope: 0.2 to 3.5
– Level: −13 to 40 K
– Maximum limit of the flow temperature: 10 to 127 °C
– Minimum limit of the flow temperature: 1 to 127 °C
■ Differential temperature for a heating circuit with mixer: 0 to 40 K
■ Setting range of the set DHW temperature:
10 to 60 °C, adjustable to 10 to 95 °C
Boiler coding card
For matching to the boiler (supplied with the boiler).
Time switch
Digital time switch (integrated into the programming unit)
■ Individual day and seven-day program, annual calendar
■ 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 time
phases per day
Shortest switching interval: 10 min
Power reserve: 14 days
Setting the operating programs
Frost protection monitoring (see frost protection function) for the heat-
ing system is enabled in all operating programs.
The following operating programs can be selected:
■ Heating and DHW
■ Only DHW
■ Standby mode
External operating program changeover possible, for all heating cir-
cuits together or separately.
Gas condensing boilers
Frost protection function
■ The frost protection function is switched on if the outside temperature
falls below approx. +1 °C, i.e. the heating circuit pump is switched
on and the boiler water is maintained at a lower temperature (see
chapter "Operating conditions with Vitotronic boiler control units").
■ "Standby mode":
The frost protection function is switched off if the outside temperature
rises above approx. +3 °C, i.e. the heating circuit pump and burner
are switched off.
■ "Heating and DHW"
The frost protection function is switched off if the outside temperature
rises above approx. +3 °C. This means the heating circuit pump is
switched off and the lower boiler water temperature for the relevant
boiler is maintained if required (see chapter "Operating conditions
with Vitotronic boiler control units").
Summer mode
("DHW only")
The burner starts only when the DHW cylinder needs reheating (con-
trolled by the cylinder temperature controller).
The respective lower boiler water temperature of each boiler is main-
tained if required.
Heating curve setting (slope and level)
The Vitotronic controls the boiler water temperature (= system flow
temperature) and the flow temperature of the heating circuits with
mixer in weather-compensated mode. The boiler water temperature is
automatically regulated to between 0 and 40 K above the highest cur-
rently 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 curve matches the boiler water temperature and
the flow temperature to these operating conditions.
The upper boiler water temperature is limited by the temperature con-
troller and the electronic maximum limiter.
110
100
90
80
70
60
50
40
30
20 15 10 5 0
Outside temperature in °C
Specification
Rated voltage
Rated frequency
Rated current
Power consumption
Safety category
IP rating
Mode of operation
Slope
1,8
1,6
1,4
1,2
1,0
0,8
0,6
0,4
0,2
-5 -10 -15 -20 -25 -30
230 V~
50 Hz
2 x 6 A~
10 W
I
IP 20 D to EN 60529
Ensure through design/
installation
Type 1B to EN 60730-1
VIESMANN
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