Viessmann VITOTRONIC 300 Installation And Service Instructions Manual page 104

Wiring, Vitotronic 300, GW5B
Connection and Wiring Diagram
Main PCB low voltage
Legend
Outdoor air temperature sensor (No function)
!
§ Boiler water temperature sensor
%A No function
%B No function
) No function
Flue gas temperature sensor
aG
aJA Therm-Control temperature sensor
or
Return temperature sensor T1
aJB Return temperature sensor T2
104
Vitotronic 300, GW5B & MW1B Installation and Service
(continued)
aVD External hook-up
aVG KM BUS participant
aVH External hook-up
LON Connecting cable for data exchange (accessory)
S3 Emissions test switch "
V1 Fault indicator (red)
V2 ON indicator (green)
X Electrical interfaces
"
S