Viessmann VITOCAL 250-A - Page 34

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Flow diagram for indoor units with 2 integral heating/cooling circuits: Heating/cooling mode for heating/
cooling circuit 2
D
E
G
F
H
A
B
C
K
Fig. 7
Air source heat pump
Heating/cooling circuit 1
Heating/cooling circuit 2
Instantaneous heating water heater
(not available with all heat pump types)
DHW cylinder
(integrated in floorstanding indoor units)
A
Return temperature sensor, secondary circuit
B
Condenser
C
Flow temperature sensor, secondary circuit
D
4/3-way valve
Positions:
DHW heating
Integral buffer cylinder or heating/cooling cir-
cuit 2
Heating/cooling circuit 1
Open flow direction
E
Flow temperature sensor, heating/cooling cir-
cuit 2
F
Heating circuit pump, heating/cooling circuit 2
G
Integral buffer cylinder
H
Heating circuit pump, heating/cooling circuit 1
K
Flow sensor
■
A voltage of 8 V is applied to the 4/3-way valve:
Position = 50 %
■
The flow temperature at the flow temperature sensor
for heating/cooling circuit 1 corresponds to the calcu-
lated set flow temperature for heating/cooling circuit
2.
■
The heating circuit pump for heating/cooling circuit 2
is switched on.
Note
If the minimum flow rate is not reached, water flows
through the integral buffer cylinder.
Function description
Heating/cooling (cont.)
6218234
Functions