Viessmann Vitocal 300 AWO-M-AC 301.A, Installation And Service Instructions Manual

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85
Plug
sXS
Terminals Function Explanation
222.3
222.4 Switching external heat
source with two high limit
safety cut-outs (max. 70 °C)
to protect the heat pump and
to stop the secondary pump Zero volt contact
Note
■ The switching contact is a zero volt N/
O contact that is closed when a heat
demand is issued.
■ Never route low voltage via this con-
tact; that requires an on-site relay.
■ The boiler water temperature sensor in
the external heat source (plug F20)
must capture the average temperature
of the external heat source.
Connection values (contact loads):
■ Voltage: 230 V~
■ Max. switching current: 4(2) A
Connect the high limit safety cut-out on
site:
■ In series to the secondary pump (ter-
minal 211.2 on the main PCB).
■ In series to the switching of external
heat sources.
Installation sequence
Electrical connections in the heat pump control…
(cont.)
5692 875 GB
Installation