Viessmann Vitocal 350-A AWHI 351.A14, Installation And Service Instructions Manual

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50
Plug sXS
Terminals Function Explanation
222.3
222.4 Control of external heat generators
and 1 high limit safety cut-out each
(on site, max. 70 °C), to switch off or
switch between the following compo-
nents:
Central heating:
■
Secondary pump, heat pump
■
External heat generator
DHW reheating:
■
3-way diverter valve "Central heat-
ing/DHW heating"
Floating contact
Note
■
The switching contact is a floating N/O contact that is
closed when a heat demand is issued.
■
Never route low voltage via this contact. For that, a
relay must be fitted on site.
■
The boiler water temperature sensor in the external
heat generator (plug F20) must capture the average
temperature of the external heat generator.
Connection values (contact load):
■
Voltage: 230 V~
■
Max. switching current: 4(2) A
Connect the high limit safety cut-out:
Central heating
■
In series to the secondary pump (connection 211.2)
■
In series for controlling external heat generators
DHW reheating
■
In series to the circulation pump for cylinder heating
(connection 211.4)
High limit safety cut-out for heat pump in conjunc-
tion with an external heat source
222.3
222.4
A
X3.1
X2.N
C
B
K1
D
Fig. 50
A
Terminals on extension PCB
B
Move jumper from X3.1 to 222.3
C
Connection on the external heat source at termi-
nals for external demand
D
High limit safety cut-out (max. 70
º
C) as heat pump
protection
K1 Relay; sizing in accordance with the external heat
source; observe safety instructions
Installation sequence
Heat pump control unit electrical connections
(cont.)
5692878
Installation