Viessmann Vitocal 300-G Installation And Service Instructions Manual page 80

Installation sequence
Connection of electrical components
Connection with temperature lim-
iter to extension kit to heating cir-
cuit M3
"Ext. demand", "Ext. mixer open", "Ext. operating mode
changeover"
These functions can also be connected via the "External extension H1". The
switching function via "External extension H1" can only be used for one function
at the time (e.g. swimming pool water heating or "Ext. demand").
Installation instructions
"External extension H1"
Note
Requires a zero volt N/O contact,
breaking capacity AC 230; 0.1 A
80
(cont.)
A Plug sÖ for extension kit
B Temperature limiter (maximum
limiter for underfloor heating sys-
tem, part no. 7151728, 7151729)
C Heating circuit pump M3
A Terminals on PCB 1
B Zero volt N/O contact (outside the
control unit)