External Hook−Up In Single Boiler Systems - Viessmann VITOTRONIC 100 Installation And Service Instructions Manual

External hook−up in single boiler systems
Operation with a two−stage burner
Zero volt contacts of the higher
control unit:
Burner stage 1 ON
Burner stage 2 ON
External changeover
of stepped/
modulating burners
External start−up
depending on load
143 146
Control unit settings
Coding "01: 1"
(delivered condition)
The boiler water temperature must
be set to the lower value. The low
temperature boiler is held at the
required minimum temperature.
The connections on plug aVD and
aVH are required when connecting
an external hook−up. The cylinder
thermostat is activated when the
cylinder temperature sensor
(accessories) is connected.
The high limit safety cut−out settings
and other settings are subject to the
system equipment and the safety
equipment in accordance with
DIN 4751 2.
Installation
69