Viessmann VITOTRONIC 200 Installation And Service Instructions Manual page 54

Function Description, Vitotronic 200/300-K
Cascade Control of the Vitotronic 300-K
54
Vitotronic 200, HO1B and 300-K, MW2C Installation/Service
(continued)
Set supply temperature
The set supply temperature is determined from the
following coding:
H Set supply temperatures of the heating circuit without
mixing valve A1 and the heating circuits with mixing
valve M2 and M3 (if installed)
H Set supply temperature of other consumers (defaulted
by the Vitotronic 200-H, for example)
H DHW temperature setpoint [Set DHW temperature]
H External demands (the set supply temperature defaulted
by coding "9b" or via input "0 to 10V" of the EA1
extension, for example)
Upper control range limits
H Maximum system supply temperature limit (coding "37"
in the "Cascade" group).
Lower control range limits
H Minimum limit of the system supply temperature
(coding "36" in the "Cascade" group).
Standalone control
Boilers connected in parallel
H Without and with supply temperature sensor.
– With supply temperature sensor: Set coding "3b:1"
in the "Cascade" group.
The control deviation is calculated from the set supply
temperature and the actual supply temperature to
determine the start and shutdown criteria.
– Without supply temperature sensor: Set coding
"3b:0" in the "Cascade" group.
To determine the start and stop criteria, the control
deviation is calculated from the set boiler water
temperature and the estimated average actual boiler
water temperature of the currently active boilers.
H The cascade control specifies the set boiler water
temperature for all currently active boilers. Every boiler
control unit regulates to the specified set value.
The following control strategies are available:
H Condensing strategy (see page 55)
H Conventional boiler strategy 1 (see page 56)
H Conventional boiler strategy 2 (see page 57)
Operation with positive pressure flue gas cascade
Coding "7e:1" in the "General" group.
When each additional boiler starts, all currently active
burners are briefly ramped up higher than 80%.