Viessmann VITOCAL 200-G Installation And Service Instructions Manual page 48

Installation sequence
Electrical connections
Plug sXS
Terminals Function
222.3 Control of external heat
222.4 sources and 1 high limit
safety cut-out each (on site,
max. 70 °C), to switch off or
switch between the follow-
ing components:
Central heating:
■ Secondary pump, heat
pump
■ External heat source
DHW reheating:
■ 3-way diverter valve for
"Central heating/DHW
heating"
48
(cont.)
Explanation
Floating 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; for that fit a relay on-site.
■ 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:
Central heating
■ In series to the secondary pump (ter-
minal 211.2 on the main PCB).
■ In series for controlling external heat
sources.
DHW reheating
■ In series to the 3-way diverter valve
(terminal 211.4 on the main PCB).