Plug
aVD
at Vitotronic 100, type GC1B and GC4B
143
B
A
1 2 3
A
Boiler blocking
B
Start boiler as the last one in the boiler sequence
A
and
B
are floating contacts.
Boiler blocking
■ Contact
A
closed:
The boiler is blocked and will be removed from the boiler sequence.
This means the butterfly valve is closed and the boiler circuit pump
is stopped. The heat demand has to be met by the other boilers.
Note
The heating system is not protected against frost if all boilers are
blocked or when no other boilers area ready for operation.
■ Contact
A
open:
The boiler is reinstated into the current boiler sequence.
Start boiler as the last one in the boiler sequence
■ Contact
B
closed:
The boiler is started as the last one in the boiler sequence.
The heat demand of the heating system is met by the other boilers.
This boiler is started if the output of the other boilers is insufficient.
■ Contact
B
open:
The boiler is reinstated into the current boiler sequence.
Connection of on-site control units to EA1 extension in multi boiler systems with on-site cascade control
unit
Control via 0 – 10 V input:
External demand via 0 – 10 V input
Connection to the 0 – 10 V input at
EA1 extension
on
each
Vitotronic
100 (accessories).
In conjunction with two-stage or modulating burners.
Set code "01:3".
U
+
L N
L
N
fÖ
S P
aBJ
Ö
[{{]
0-10V
f-]
A
+ -
Enable boiler without an additional enable contact
0 to 1 V
■ Boiler blocked.
■ Butterfly valve closed.
■ Boiler circuit pump or shunt pump off.
1 to 10 V
■ Boiler water temperature default
1 V
≙
Set value 10 °C
10 V
≙
Set value 100 °C
■ Boiler enabled; held at minimum temperature.
■ Butterfly valve open.
■ Boiler circuit pump or shunt pump enabled.
Note
Only for low temperature boilers:
On the lead boiler, the voltage must be higher than 1 V.
Note
Ensure DC separation between the negative pole and the earth con-
ductor of the on-site voltage source.
Enable boiler with an additional enable contact
0 - 1 V
≙
"No default set boiler water temperature"
1 V
≙
Set value 10 °C
10 V
≙
Set value 100 °C
146
A
1 2 3
A
Boiler enable
(floating contact)
Note
This contact must always be closed on the lead boiler.
Contact Closed
Open
A
Boiler enabled; held at min-
imum temperature. The but-
terfly valve opens.
The butterfly valve is closed
after approx. 5 min. External
burner start not possible.
Digital data inputs DE1 to DE3
Functions:
■ External blocking
■ External blocking with fault message input
■ Fault message input
The hooked-up contacts must correspond to safety category II.
Control units
(cont.)
Gas condensing boilers
VIESMANN
91
5822 449 GB
9