Technical data

84
Installation – Vitocontrol-S, VD2/CT3/CM2
Connection of external contacts
A External heating program
changeover or mixing valve “open”
Contact closed:
The manually pre-selected heating
program can be changed via this
contact, (see table below) enabling the
mixing valves to be opened.
The mixing valve open function can be
allocated via coding address “9A”, and
the heating program changeover can be
allocated to the heating circuits via
address “91”.
¨Heating circuits are no longer frost
protected during mixing valve closed. A
minimum boiler return temperature is
not maintained during external
disabling.
Via coding address “99”, you can
pre-select what input aVD should
affect.
A External heating program
changeover/external mixing valve
B External disable/external mixing
valve “closed”
C External override
B External disable/external mixing
valve “closed”
Closing the dry contact causes the
burner to shut down or the mixing
valve to be closed.
Allocated boiler or shunt pumps are
switched OFF, and isolation valves are
closed.
C External demand
Closing the dry contact starts the boiler
burners, subject to load via a set
supply temperature (coding address
“9b”) on Vitocontrol-S, VD2/CT3.
The supply temperature is limited via
the set min. and max. supply
temperature.
Manually pre-selected
heating program
(with open contact)
Coding 2 Changed heating program
(with closed contact)
9
or
Room heating OFF/
DHW OFF
d5: 0
(factory
default)
<–> Continuous operation with reduced room temperature/DHW OFF
w
or
Room heating OFF/
DHW ON
d5: 1 <–> Continuous operation with normal room temperature/DHW in
accordance with coding address “64”
rw Room heating ON/
DHW ON
5351 340 v1.4
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146
A
B
C