Viessmann Vitocal 300-G Installation And Service Instructions Manual page 178

Connection and wiring diagrams
PCB 2: Function components 230 V
w¢Z Mixer motor, heating circuit M2 -
CLOSE
w¢U Circulation pump, heating
circuit M2
w¢I Cylinder primary pump (in case
of a primary system at the DHW
cylinder, shut-off valve)
w¢O Control of electric immersion
heater EHE for DHW cylinder
wYP Control of external heat source
wYQ Instantaneous heating water
heater control (stage 2)
wYW Control of AC-Box and relay for
separate cooling circuit pump
Connection markings
Terminal strip X7:
Terminals 2X7.1 to 2X7.13
Terminal strip X8:
Terminals 2X8.1 to 2X8.13
Function components 230 V on PCB 2 (motherboard, terminal strip X7)
Function
Control/demand of the ex-
ternal heat source
178
(cont.)
wYE Mixer motor, external heat
source - OPEN
wYR Mixer motor, external heat
source - CLOSE
wYT Circulation pump, direct heating
circuit A1 (if heating water buffer
cylinder is installed)
wYZ Circulation pump for cylinder
heating (in case of a cylinder pri-
mary system on the heat pump)
wYU DHW circulation pump
wYI Central fault message (zero volt
contact in the 230 V range)
wYO AC-Box
wXP NC-Box
For PCB overview, see from page 61.
Note
Total load of all electrical connec-
tions max. 1000 W.
Terminals may already have been
allocated (subject to appliance ver-
sion). If this signal is required exter-
nally, completely remove the core or
insulate the core end; alternatively
use a twin wire ferrule.
The connections to neutral conduc-
tors and earth conductors are not
shown in the following list. These
are made at PCB 1 (cross current
circuit board) at terminals strips
1X1.? (earth conductor) and 1X2.N
(neutral conductor)
Explanation
Zero volt N/O contact:
Closed = demand
Open = no demand
Breaking capacity 250 V~, 4(2) A
unsuitable for safety LV ( 42 V~)
Connection
2X7.1
2X7.2