Viessmann Vitocal 350-A Installation And Service Instructions Manual page 77

Electrical connections in the heat pump control...
Terminal strips on PCB 1 A (cross con-
nect PCB):
X1 Terminals for earth conductor
"?"
X2 Terminals for neutral conductor
"N"
X3 Terminals for power supply to
the heat pump control unit "L1"
and auxiliary components
X5/X7 Terminal strips for connecting
cable (control cable 230 V~)
Terminal strips on PCB 2 C (main
PCB):
X7 External 230V~ connections
■ DHW circulation pump ("Wtimer
DHW Circ.")
■ Heating circuit pump for heating
circuit without mixer A1
■ Circulation pump for cylinder
heating
■ Instantaneous heating water
heater control, stage 2
■ Mixer motor control, external
heat source
■ Central fault message
X8 External 230 V~ connections
■ Circulation pump for DHW
reheating
or
Control of immersion heater (on
site)
■ Cylinder primary pump / two-way
shut-off valve
■ Heating circuit pump for heating
circuit with mixer M2
■ Mixer motor control, heating cir-
cuit M2
■ Secondary pump
■ Instantaneous heating water
heater control, stage 1
X9 Internal connections
Installation sequence
X10 Internal connections
X11 Terminals
X15 Programming unit connection
X16 Internal connections
Terminal strips on PCB 3 E (sensor
PCB):
X1 KM BUS and sensor connec-
tions:
■ Outdoor temp.
■ Heating water buffer cylinder
temperature
■ Boiler temperature, external
heat source
■ Flow temperature, heating cir-
cuit with mixer M2
■ System flow temperature
■ Secondary circuit flow temper-
ature
■ DHW cylinder temperature,
top/bottom
■ Remote control connection for
heating circuits with/without
mixer A1, M2, M3
X2 Common earth connection
(GND)
X5/X6 Terminal strips for connecting
cable (LV cable)
Note
As some terminal strip designations
occur more than once (e.g. X1), they will
be preceded in the following by the PCB
number.
Example:
3X1.2: PCB 3, terminal strip X1, termi-
nal 2
1X1. ? : PCB 1, terminal strip X1, any
earth terminal
1X2.N: PCB 1, terminal strip X2, any
neutral conductor terminal
(cont.)
77