External Extensions (Accessories) - Viessmann FB2A Installation And Service Instructions For Contractors

Function description

External extensions (accessories)

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
110
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 function "Exter-
nal heating program change-
over" is set via coding address
"91"
aVF External set value 0 to 10 V
aVG KM BUS