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

External hook−up in multi−boiler systems with LON
Zero volt contacts of the higher
control unit:
Boiler blocking
Start boiler as last
one in boiler
sequence
External changeover
of stepped/
modulating burners
143 146
Control unit settings
Set code "01: 2".
Starting boiler as last one in boiler
sequence
Contact closed:
The boiler is started as the last one
in the boiler sequence.
The heat demand of the heating
system is being met by the other
boilers. This boiler is started if the
other boilers do not provide
sufficient heat.
Contact opened:
The boiler is reinstated into the
current boiler sequence.
Boiler blocking
Contact closed:
The boiler is blocked.
It is taken out of the boiler sequence,
i.e. the butterfly valve or the
three−way mixing valve for constant
return temperature control is closed;
shunt or boiler circuit pumps are
switched OFF . The other boilers must
provide the required heating.
!
Please note
The heating system is no
longer protected against frost if
all boilers are blocked or there
are no other available boilers.
Contact opened:
The boiler is reinstated into the
current boiler sequence.
External changeover of
stepped/modulating burners
Contact open:
Contact closed:
operation
Code "02: 2" (modulating burner)
must be selected.
Note
Even if the contact is closed,
scanning the type of burner will
continue to display "modulating".
Installation
mod. mode
two−stage
83