Viessmann VITOTRONIC 300 GW2 Installation And Service Instructions Manual page 16

Heating system types
Heating system types for condensing boilers
System type 5 – Single-boiler system with Vitocrossal 200
A Boiler with Vitotronic 300
B Domestic hot water tank
C Heating circuit with mixing valve
D Neutralizing unit
16
plugs
! Outdoor temperature sensor
? M2 Supply temperature sensor,
mixing valve circuit 2
? M3 Supply temperature sensor,
mixing valve circuit 3
§ Boiler temperature sensor
% DHW tank temperature sensor
sÖ A1 Heating circuit without mixing
valve (if installed)
sÖ M2 Heating circuit pump, mixing
valve circuit 2
sÖ M3 Heating circuit pump, mixing
valve circuit 3
sA Circulation pump for heating
the DHW tank
DHW re-circulation pump
sK
Power supply connection,
fÖ
120 VAC
fA Burner (1st stage)
gS M2 Mixing valve motor, mixing
valve circuit 2
gS M3 Mixing valve motor, mixing
valve circuit 3
lÖ Burner (2nd stage/modulating)
aVD Connection of external
equipment (see page 38)
Connection of external
aVH
equipment (see page 39)