Viessmann VITOCAL 300-G PRO Installation And Service Instructions Manual page 67

Overview of electrical connections
Terminals Function
LP1 X3.12 Signal "External demand"
LP1 X3.13 (external starting of com-
or at H1 ex- pressor and pumps, mixer
ternal ex- in control operation or
tension OPEN, changeover of op-
erating mode of several
system components)
K2 220.2 Only for 2-stage heat
pumps:
K2 220.3 Blocking compressor 2 in
connection with DHW
heating
STB 1 High limit safety cut-out
STB 2 (max. 70 °C) for stopping
the secondary pump in
conjunction with an exter-
nal heat generator
(cont.)
Explanation
Requires floating N/O contact:
■ Closed: Demand
■ Open: No demand
■ Breaking capacity 230 V, 2 mA
Note
■ These and further external functions,
such as swimming pool water heating,
cascade or external set value default
can alternatively be connected via H1
external extension (see installation in-
structions "H1 external extension").
■ If a swimming pool heating facility is con-
nected to H1 external extension, no oth-
er external function can be connected to
H1 external extension.
Connection, see separate "Connection
and wiring diagram" sheet 20.
Connection in series with the secondary
pump (terminal 211.2 on main PCB), see
separate "Connection and wiring diagram"
sheet 20.
Installation sequence
67