Viessmann VITOCAL 350-A Installation And Service Instructions Manual page 56

Installation sequence
Electrical connections: Heat pump control unit
High limit safety cut-out for heat pump in conjunc-
tion with external heat generator
X3.1
B
222.3
A
222.4
D
K1
X2.N
Fig. 54
Terminals on extension PCB
A
Connect jumper across X3.1 and 222.3.
B
C Connection on external heat generator to terminals
for "External demand"
High limit safety cut-out to protect the heat pump
D
(max. 70 °C)
K1 Relay
Sizing according to the external heat generator
■
Observe safety instructions.
■
Plug sXD
Terminals Function
223.1 Central fault message
223.2
U
Central fault message
223.1
A 230V~, 0.5 A
223.2
Fig. 55
Terminals on extension PCB
A
56
C
L1
N
(cont.)
Explanation
Floating contact:
Closed: Fault
■
Open: No fault
■
Not suitable for safety LV
■
Connection values (contact rating):
Voltage: 230 V~
■
Max. switching current: 4(2) A
■