Viessmann VITODENS 200-W Service Instructions Manual page 96

Function description
Extensions for external connections...
External extension H1
The external extension is connected to
the boiler control unit via the KM BUS.
The following functions can be controlled
or processed simultaneously via the
extension:
A ON/OFF switch (on site)
sÖ Heating circuit pump for the heat-
ing circuit without mixer
sA Circulation pump for cylinder heat-
ing
sK DHW circulation pump (only for
weather-compensated operation)
fÖ Power supply
gÖ Central fault message
96
(cont.)
aVD ■ External blocking
(terminals 2 - 3)
■ External demand
(terminals 1 - 2)
■ External heating program
changeover (terminals 1 - 2)
(only for weather-compensated
operation)
The allocation of the function
"External heating program
changeover" is set via coding
address "91".
aVF External set value 0 to 10 V
aVG KM BUS