Viessmann Vitocal 300-G Installation And Service Instructions Manual page 90

Installation sequence
Electrical connections
Plug Sensor
X24 Connection of the LON communication module (plug in
on site, see LON communication module installation
instructions)
X31 Coding card slot
Connection of primary circuit flow/return temperature sensor, two-stage heat
pump
aS
aS
[G
X
aD
aS Flow temperature sensor, primary
circuit
90
(cont.)
2.
aD
< 42 V
3.
aS
aD Return temperature sensor, primary
circuit
Type
1.
aS
aD
aS
aD
aD