Viessmann VITOTRONIC 300 Installation And Service Instructions Manual page 108

Wiring, Vitotronic 300-K
Connection and Wiring Diagram
PCB low voltage
Legend
Outside temperature sensor
!
? Supply temperature sensor
%A DHW tank temperature sensor
%B DHW tank temperature sensor 2 for primary store
system)
No function
)
aG No function
aJA No function
aJB Return temperature sensor T2
or
Temperature sensor primary store system
108
Vitotronic 300, GW5B & MW1B Installation and Service
(continued)
External hook-up
aVD
aVG KM BUS participant
External hook-up
aVH
LON Connecting cable for data exchange (accessory)
S3 Emissions test switch "
V1 Fault indicator (red)
V2 ON indicator (green)
X Electrical interfaces
S "