Viessmann Vitocal 350-A Installation And Service Instructions Manual page 207

Overview of the PCBs and connection options
Signalling and safety connections at PCB 1 (cross connect PCB)
Pos. Function
q¢Q ON/OFF switch
q¢W External blocking, mixer
CLOSED
q¢E External demand to the
heat pump; mixer OPEN;
operating mode change-
over
q¢R Fault message, lag heat
source
q¢T
Jumper in safety chain
q¢Z
Power-OFF
q¢U Jumper fitted at the fac-
tory
q¢I Appliance fuse F1 ( 6.3 A
(slow))
qYP Phase switched
Connection and wiring diagrams
Explanation
Zero volt contact:
■ Closed: Blocking enabled
■ Open: No blocking
■ Breaking capacity 230 V, 0.1 A
On-site connection
Zero volt contact:
■ Closed: demand
■ Open: No requirement
■ Breaking capacity 230 V, 0.1 A
On-site connection
Zero volt contact:
■ Closed: No fault
■ Open: Fault
■ Breaking capacity 230 V, 0.1 A
Connection on site; remove
jumper when connecting
Zero volt contact:
■ Closed: No blocking (safety
chain has continuity)
■ Open: Blocking enabled
■ Breaking capacity 230 V, 0.5 A
Connection on site; remove
jumper when connecting
(cont.)
Terminals
1X2.2
1X2.3
1X3.16
1X3.17
1X3.2
1X3.14
or to exter-
nal exten-
sion H1
1X3.13
1X3.12
or to exter-
nal exten-
sion H1
1X3.11
1X3.10
1X3.8
1X3.9
1X3.7
1X3.6
1X3.3
1X3.4
1X3.1
207