Boiler Sequence Control With On-Site Cascade Control Unit — Connections To The Vitotronic 100, Type Gc1B - Viessmann VITOCROSSAL 200 Type CM2 Technical Manual

Control units
(cont.)
Input function assignment
Select the input functions via the codes on the boiler control unit:
■ DE1: Coding address "5d"
■ DE2: Coding address "5E"
■ DE3: Coding address "5F"
Boiler sequence control with on-site cascade control unit — connections to the Vitotronic 100, type GC1B
Control via contacts:
Operation with a two-stage burner
9
1 2 3 1 2 3
143 146
A Burner stage 1 "on"
B Burner stage 2 "on"
C Boiler enable
Butterfly valve "Open" or "Closed"
A, B and C are floating contacts of the higher ranking control
unit.
The connections on plugs aVD and aVH are required when connecting
an external control unit. The cylinder temperature and the load-
dependent cascade control must be controlled by an external control
unit.
Note
An "enable boiler" contact is essential for multi-boiler systems.
This contact must always be closed on the lead boiler.
External burner start – burner stage 1
Contact at terminals "1" and "2" of plug aVD
■ Contact closed:
Burner stage 1 is switched ON.
Burner stage 2 is switched ON only for maintaining the minimum
temperature.
The boiler water temperature is limited by the electronic maximum
temperature limiter (see the Vitotronic 100 service instructions), if it
is set below that of mechanical thermostat "R".
■ Contact open:
Burner stage 1 is switched OFF.
VIESMANN
92
A
B
C
External burner start – burner stage 1 and 2
Contact at terminals "2" and "3" of plug aVD
■ Contact closed:
Both burner stages are switched ON.
The boiler water temperature is limited by the electronic maximum
temperature limiter, if it is set below that of mechanical control ther-
mostat "R".
Burner stage 2 is switched OFF 2 K sooner.
■ Contact open:
Burner stages 1 and 2 are switched OFF.
Enable boiler, butterfly valve
Contact at terminals "2" and "3" of plug aVH
■ Contact closed:
Initially, the preheat function for lag boilers is activated.
After the preheat function has expired, the minimum boiler water
temperature will be maintained and the burner stages can be con-
trolled externally.
■ Contact open:
The butterfly valve is closed after approx. 5 min.
Burner stages cannot be switched ON externally; a minimum tem-
perature will not be maintained.
Settings at the Vitotronic 100
Code "01:3".
The high limit safety cut-out settings and other settings depend on the
system equipment level along with safety equipment to DIN EN 12828
or DIN EN 12953.
High limit safety cut-out
Temperature controller
Coding address "06" for electronic maxi-
mum temperature limiter (Vitotronic
100)
Maximum temperature of the on-site con-
trol unit
110 °C 100 °C
100 °C 87 °C
95 °C 85 °C
90 °C 80 °C
Gas condensing boilers