Viessmann VITOCAL 300-A Installation And Service Instructions Manual page 91

Electrical connections in the control unit
Required parameter (code to be entered by "Contractor": 5243)
Function
External blocking
External mixer "CLOSE"
Central fault message
A Terminals on PCB 2
Zero volt contact, open in fault-
free operation (voltage > 42 V)
Breaking capacity 230 V~; 4(2) A
Note
& No parameters need to be set.
&
The contact issues a short pulse
when the power supply is switched
on. Observe the pulse when proces-
sing the message via communica-
tion tools.
Connecting external components
Note
Only one function (e.g. external demand) or one component (e.g. swimming
pool water heating) can be connected to external extension H1.
Installation sequence
(cont.)
Parameter (ID) Ó Setting
"System definition"
"Ext. blocking effect" (701A) Ó
&
"0" to "31" (see page 140)
"System definition"
"Ext.blocking/Miclose" (7015) Ó
&
"0" to "8" (see page 138)
Observe parameter "Ext. blocking
effect" (701A) (see page 140).
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