Viessmann VITOCAL 300-A Installation And Service Instructions Manual page 171

Overview of the PCBs and connection options
Pos. Function
wYI
Central fault message
PCB 2, terminal X8
Pos. Function
End of safety chain
Compressor control via
refrigerant circuit
N/A
Fan control
w¢E
Secondary pump
w¢R
Control of instantaneous
heating water heater,
stage 1
w¢T
Control of the mixer
motor, heating circuit M2,
signal OPEN
w¢Z
Control of the mixer
motor, heating circuit M2,
signal CLOSE
Connection and wiring diagrams
Explanation
Zero volt contact:
&
Closed: Fault
&
Open: No fault
&
Contact breaking capacity
250 V~, 4(2) A
&
Not suitable for safety LV
On-site connection
Explanation
'Live' in case of fault-free safety
chain
& Heat demand: Contact closed,
2X8.2 is 'live'
& If the compressor will not
start, check whether it has
been enabled by the refriger-
ant circuit (electronic expan-
sion valve EEV controller)
(own relay on EEV PCB, see
page 178)
Internal connection
N/A
Internal connection
& In systems without a heating
water buffer cylinder, the sec-
ondary pump is sufficient (see
terminals 2X7.9)
& Max. output: 130 W
On-site connection
Accessories
& Output 10 W
On-site connection
& 230 V
On-site connection
& 230 V
On-site connection
(cont.)
Terminals
2X7.12
2X7.13
Terminals
2X8.1
2X8.1
2X8.2
2X8.3
2X8.4
2X8.5
2X8.7
2X8.8
2X8.9
2X8.10
171