Viessmann EM-EA1 Installation And Service Instructions Manual page 5

Rotary switch S1
Connecting the PlusBus to the heat generator control unit
A
jF jF [{] DI1 DI2 DI3 [{]
1 2 3 4 5 6
1 2 3 4
A Extension
B PlusBus to heat generator
[{]
B
Rotary switch S1 must be set to 1 (fac-
tory setting).
Note
If making the connection to the heat
generator with an external plug for the
bus connection, disconnect plug jF
and connect the wires directly.
Heat generator installation and
service instructions
5