External Heating Program Changeover/External Demand; External Blocking - Viessmann Vitoladens 300-C Installation Instructions Manual

External connections at plug . . .
A External heating program change-
over/external demand (zero volt
contact)
B External blocking (zero volt con-
tact)

External heating program changeover/external demand

The manually preselected heating
program can be modified and an
external demand be received via the
contact.
The heating program changeover can
be allocated to the heating circuits via
coding address "91".

External blocking

Closing the zero volt contact causes
the burner to shut down.
Note
To ensure frost protection, the boiler
is switched ON when the actual tem-
perature falls below 5 °C; the boiler
water is then heated up to 15 °C.
26
(cont.)
A minimum boiler water temperature
can be defaulted via coding address
"9b", and an additional function can
be programmed for the circulation
pump via coding address "34".
An additional function for the circula-
tion pumps can be programmed via
coding address "32".
Boiler service instructions