External Demand Via Switching Contact - Viessmann Vitotronic 300 GW6B Installation Instructions Manual

Electrical Connections

External Demand via Switching Contact

Plug aVH.2/aVH.3
146
Legend
A Floating contact
B Plug aVH of the control unit
EA1 extension
Legend
A Floating contact
B EA1 extension
42
Vitotronic 300, GW6B Installation and Service
Only for single boiler and cascade control units
Connection options:
H Plug aVH.2/aVH.3
H EA1 extension (accessory, see page 122)
Contact closed:
H Single boiler system
The burner is switched ON subject to load. The boiler
heats to the set boiler water temperature selected in
coding "9b" in the "General" group.
Limiting the boiler water temperature by means of the
set boiler water temperature and the electronic
maximum limit of the boiler water temperature
(coding "06" in the "Combustion Controller" group)
H Multi boiler system
The burners in each boiler are switched ON subject to
load. They heat to the set supply temperature selected
in coding "9b" in the "General" group.
Limiting the supply temperature by means of the set
supply temperature and the electronic maximum limit
of the supply temperature (coding "37" in the
"Cascade" group)
Connection
Note: 'Live' contacts lead to short circuits or phase failure.
The external connection must be potential-free.
Coding
Plug aVH
No coding change required
EA1 extension
Set "5d" (DE1), "5e" (DE2) or "5f" (DE3) in group
"General" to 2.