Viessmann VITOCAL 300-G Technical Manual page 25

Design information
Two-stage heat pump
D
E
F
G
H
K
C
A Heat pump type BW, WW (stage 1)
B Heat pump type BWS (stage 2)
C DHW cylinder
D Outside temperature sensor, sensor lead (2 x 0.75 mm
E DHW circulation pump, power cable (3 x 1.5 mm
F Cylinder temperature sensor, sensor lead (2 x 0.75 mm
G Junction box
H Motorised two-way valve, normally closed
K Cylinder primary pump (DHW side), power cable (3 x 1.5 mm
L Circulation pump for cylinder heating (heating water side), power
2
cable (3 x 1.5 mm )
or
Three-way diverter valve, power cable (5 x 1.5 mm
Recommendation: use the circulation pump for cylinder heating
as hydraulic balancing is better achieved than with the three-way
diverter valve.
Two circulation pumps for cylinder heating are required for the
two-stage heat pump (one for every stage; see page 31).
M Circulation pump, primary circuit (brine), power cable (3 x
2
1.5 mm or
for circulation pump with thermal circuit breaker 5 x 1.5 mm
If a 400 V~ circulation pump is used, it should be connected via a
contactor relay.
With the two-stage heat pump, either a common primary pump
can be used for both stages, or a separate primary pump can be
used for each stage.
Type WW: Note the following additional components:
■ Well pump (If a 400 V~ well pump is used, it should be connected
via a contactor relay.)
■ Flow limiter
■ Frost stat
■ Separating heat exchanger
Recommended power cables:
Type
BW 121, WW 121
BWS 121
BW 129, WW 129
BWS 129
BW 145, WW 145
BWS 145
Line lengths in the heat pump plus wall clearance:
Type
Heat pump control unit power supply (230 V~) 1.0 m
Compressor power supply (400 V~)
Additional power cables
VITOCAL 300-G
(cont.)
O
P
M
R
N
L
A
B
2
)
2
)
2 )
2
)
2
Heat pump control unit
(230 V~)
2
5 x 1.5 mm
—
5 x 1.5 mm 2
—
5 x 1.5 mm 2
—
BW, WW
1.0 m
1.5 m
U
S
T
N Electrical connecting cables between heat pump stage 1 and 2
(standard delivery)
O Secondary pump, power cable (3 x 1.5 mm
Two secondary pumps are required for the two-stage heat pump
(one for every stage; see page 31).
Further circulation pumps are required for heating water buffer
cylinders, heating circuits with mixers and external heat sources;
see system scheme, page 33.
P Instantaneous heating water heater (on site):
2 )
An instantaneous heating water heater (on site) can only be
installed outside the heat pump. The flow temperature sensor
system must be installed in the direction of flow downstream of
the instantaneous heating water heater.
■ Power cable: See details provided by manufacturer
■ Control via heat pump control unit
R Heat pump control unit power cable, 230 V~, 50 Hz (5 x
1.5 mm 2 ) with power-OFF contact
S Compressor power cable, type BW, WW, 400 V~ (see table)
T Compressor power cable, type BWS, 400 V~ (see table)
U Electricity meter/mains
)
Note
For heating water buffer cylinders, heating circuits with mixers, exter-
nal heat sources (gas/oil/wood) etc., additional supply and control
cables and sensor leads must be factored in.
Check the core cross-section of the power cables and enlarge if
required.
Compressor (400 V~)
2
4 x 2.5 mm
4 x 2.5 mm 2
4 x 4.0 mm 2
2
4 x 4.0 mm
4 x 6.0 mm 2
2
4 x 6.0 mm
BWS
A connecting cable is used for the power sup-
ply
1.0 m
Connecting cable
2 )
Max. cable length
50 m
50 m
50 m
50 m
40 m
40 m
VIESMANN
3
25