Boiler Sequence Control With On-Site Cascade Controller — Connections To The Vitotronic 100, Type Gc1 - Viessmann VITOPLEX 200 Type SX2A Technical Manual

Control units
(cont.)
External burner start – burner stage 1
Contact at terminals 1 and 2 of plug aVD
■ Contact closed:
Burner stage 1 is switched on.
The modulation (full load) 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 the mechanical thermostat "R".
■ Contact open:
Burner stage 1 is switched off.
Modulating burner connection:
■ Burner stage 1 fA of the Vitotronic 100
■ Plug lÖ from the Vitotronic 100 via modulation controller (on-site) to
plug lÖ on the burner.
■ Set the minimum temperature at the higher control unit with the
modulation controller 5 K higher than the lower boiler water temper-
ature; see operating conditions.
Adjustments at the Vitotronic 100
■ Code "01:1" (delivered condition)
■ The boiler water temperature must be set to the lower value (see
operating conditions, pages 5 to 11).
The minimum boiler temperature is maintained (see operating con-
ditions, pages 5 to 11).
Boiler sequence control with on-site cascade controller — Connections to the Vitotronic 100, type GC1
Operation with a two-stage burner
1 2 3 1 2 3
143 146
A Burner stage 1 "ON"
B Burner stage 2 "ON"
C Enable boiler
Butterfly valve "open" or "closed"
A, B and C are zero volt contacts of the higher 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.
OIL/GAS BOILERS
A
B
C
■ The cylinder thermostat is activated when the cylinder temperature
sensor is connected.
■ The high limit safety cut-out settings and other settings depend on
the system equipment level and the safety equipment to EN 12828
or EN 12953.
High limit safety cut-out
Temperature controller
Coding address "06" for electronic max-
imum temperature limit (Vitotronic 100)
Maximum temperature of the on-site
control unit
Note
A safety temperature of 120 °C (EN12953) is only permissible with
an additional, self-monitoring high limit safety cut-out. For an acces-
sory pack for safety temperature 120 ºC, see Viessmann pricelist.
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.
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.
Adjustments at the Vitotronic 100
Code "01:3".
110 °C 100 °C
100 °C 87 °C
95 °C 85 °C
90 °C 80 °C
11
VIESMANN
73