Viessmann Vitoligno 300-C Installation And Service Instructions Manual page 164

Connection and wiring diagram
Position of the PCBs
Danger
Touching live components can result in life
threatening injuries. After switching off the
ON/OFF switch on the control unit, there are still
live components inside the control unit enclo-
sure.
Isolate the system from the power supply, e.g.
■
by removing the separate fuse or by means of
a mains isolator, and check that it is no longer
live.
■ Safeguard the system against reconnection.
164
A
Fig. 90
PCBs in the control unit wiring chamber
A
■ ZPK 2.02
Auxiliary PCB: Control of the fuel charging and
cleaning systems
■ HKK 2.01
Heating circuit PCB: Control of the heating cir-
cuits, DHW heating and solar
■ KSK 2.03
Main PCB: Burner control unit, KM-BUS,
CAN bus, buffer temperature sensors, control of
automatic return temperature raising facility