Viessmann Vitodens 300 Service Instructions Manual page 110

Designs
Connection and wiring diagrams – external connectio . . .
A3 Optolink
A4 Burner control unit
A5 Operating interface
A6 Coding card
A7 Connection adaptor
A8 LON communication module
A9 Internal extension H1
S1 ON/OFF switch
S2 Reset button
!
Outside temperature sensor
?
Flow temperature sensor low
loss header
%
Cylinder temperature sensor
110
sÖ
Internal circulation pump
(heating circuit pump or boiler
circuit pump)
sK
Circulation pump or central fault
message
dD
Flow switch
dG
Gas solenoid valve
fÖ
Power supply
gD
External LPG safety valve
lH
Mains power supply - acces-
sories and Vitotrol 100
a-Ö Fan motor
aYA Gas governor
aVG KM BUS
(cont.)