Viessmann Vitoplus 300 Service Instructions Manual page 90

Function description
Extensions for external connections . . .
External extension H2
The external extension is connected
to the boiler control unit via the KM
BUS. The following functions can be
controlled or processed via the exten-
sion:
sK DHW circulation pump
fÖ Power supply
90
(cont.)
aVD External blocking
(terminals 2 - 3)
External demand
(terminals 1 - 2)
External operating mode chan-
geover (terminal 1 - 2)
The allocation of the "External
operating mode changeover"
function is selected via coding
address "91".
aVG KM BUS