Viessmann Vitocal 300-G Installation And Service Instructions For Contractors page 78

Installation sequence
Electrical connections in the heat pump control...
High limit safety cut-out for heat
pump in conjunction with an external
heat source
X3.1
222.3
A
222.4
D
K1
X2.N
A Terminals on extension PCB
B Move jumper from X3.1 to 222.3
Plug sXD
Terminals Function
223.1 Central fault message
223.2
U
78
B
C
C Connection on the external heat
source at terminals for external
demand
D High limit safety cut-out (max. 70
°C) as heat pump protection
K1 Relay; sizing in accordance with the
external heat source; observe
safety instructions
Explanation
Zero volt contact:
■ Closed: Fault
■ Open: No fault
■ Unsuitable for safety LV.
Connection values (contact loads):
■ Voltage: 230 V~
■ Max. switching current: 4(2) A
Connect on site.
Note
■ No parameters need to be set.
■ The contact issues a short pulse when
the power supply is switched on.
Observe the pulse when processing
the message via communication tools.
(cont.)