Viessmann Vitocal 300-G Installation And Service Instructions Manual page 180

Connection and wiring diagrams
PCB 2: Function components 230 V
Function
Central fault message
Function components 230 V on PCB 2 (motherboard, terminal strip X8)
Function
End of safety chain
Compressor control via
controller of the electronic
expansion valve (EEV)
N/A
Primary pump, well pump
control
Natural cooling control
Secondary pump
180
(cont.)
Explanation
Zero volt contact:
closed=fault
open=no fault
Contact breaking capacity 250 V~,
4(2) A
unsuitable for safety LV
Explanation
'Live' in case of fault-free safety
chain
Control internal contact between
2X8.1 and 2X8.2 is closed in case
of heat demand.
2X8.2 is 'live'
If the compressor fails to operate,
the enable signals from the EEV
controller via a suitable relay to the
EEV PCB may be missing.
N/A
Pmax.=200 W
Observe the information regarding
the total current drawn (from the
table)!
Observe the information regarding
the total current drawn (from the
table)!
This control signals is additionally
required with the AC-Box.
In systems without heating water
buffer cylinder, the secondary
pump is sufficient (see terminals
2X7.9 on page 179)
Pmax.=130 W
Observe the information regarding
the total current drawn (from the
table)!
Connection
2X7.12
2X7.13
Connection
2X8.1
2X8.2
2X8.3
2X8.4
2X8.5
2X8.6
2X8.7