Viessmann VITOCAL 300-A Installation And Service Instructions Manual page 172

Connection and wiring diagrams
Overview of the PCBs and connection options
Pos. Function
w¢U
Heating circuit pump of
the heating circuit with
mixer M2
w¢I
Cylinder primary pump,
two-way shut-off valve
(for installation position
see page 37)
w¢O
Circulation pump for cy-
linder reheating through
an external heat source
for DHW heating
or
Electric immersion hea-
ter control (on site) for
the DHW cylinder
172
Explanation
&
Max. output: 100 W
On-site connection
Switch cylinder primary pump
and two-way shut-off valve in
parallel
&
Max. output: 130 W
On-site connection
The connection can be used to
control an electric immersion
heater (on site) in the DHW cy-
linder if the external heat source
is not used for DHW heating.
On-site connection
(cont.)
Terminals
2X8.11
2X8.12
2X8.13