Viessmann Vitotronic 300 Installation And Service Instructions Manual page 12

Installation Sequence
Overview of Electrical Connections
Legend
Extension for heating circuits 2 and 3 with mixing valve
(accessory module supplied separately)
?M2/M3 Supply temperature sensor
sÖM2/M3 Heating circuit pump
gSM2/M3 Mixing valve motor
PCB, low voltage
! Outdoor temperature sensor (ATS)
%A DHW temperature sensor
%B DHW temperature sensor 2 for primary store
system (optional accessory, not used)
Supply temperature sensor, low loss header
)
(optional accessory)
aJ B Temperature sensor primary store system
(optional accessory, not used)
aVD External hook-up
KM BUS participant e.g. Vitotrol Remote (accessory)
aVG
External connection
aVH
PCB 120V/60Hz
sÖA1 High temperature circuit pump
sA DHW circulation pump
DHW recirculation pump
sK
Accessories pump
sL
Power supply, 120V/60 Hz
fÖ
Burner (call for heat)
fA
Central fault message
gÖ
gSA1 Isolation valve
or
3-way mixing valve, primary store system (optional
accessory, not used)
External connections, e.g. supplementary safety
aBÖ
equipment
aBA Safety chain, potential free
Power supply for accessories
aBH
12
Vitotronic 300, GW5B Installation and Service
(continued)
Inserting cables and applying strain relief
Control unit fitted on the side of the boiler:
Route cables from below out of the cable
trunking into the control unit.