Viessmann VITOCAL 222-S Installation And Service Instructions Manual page 60

Installation sequence
Electrical connection
Connecting internal and external unit
Vitocal 222-S, type AWT-AC
221.A04
C N L ?
A
B
12V COM COM 43V
A Wiring chamber, external unit (see
page 59)
B BUS cable between the external
and internal unit
Recommended cable: 3 x 1.5 mm
The cores are not interchangeable.
C AVI PCB in the internal unit (see
page 50)
60
(cont.)
221.A07
Ni
COM
?
C
C
12V COM
2
221.A10 and A13
Li N L
?
0 0
C2 C1
A
B
COM 43V
12V COM
Note
Route BUS cable for internal/external
unit in the 230 V~ voltage area.
N L ? N L
?
A
B
C
COM 43V