Wellea Monobloc
18
4.4
Four-way Valve Control
The four-way valve is used to change the direction of refrigerant flow through the water side heat exchanger in order to
switch between cooling and heating/DHW operations. Refer to Figures 2-3.1 and 2-3.2 in Part 2, 3 “Refrigerant Flow
Diagrams”.
During heating and DHW operations, the four-way valve is on; during cooling and defrosting operations, the four-way
valve is off.
4.5
Electronic Expansion Valve Control
The position of the electronic expansion valve (EXV) is controlled in steps from 0 (fully closed) to 480 (fully open).
At power-on:
The EXV first closes fully, then moves to the standby position (304 (steps)). After 30 seconds the EXV moves to an
initial running position, which is determined according to operating mode and outdoor ambient temperature.
After a further 150 seconds, the EXV is controlled according to suction superheat and discharge temperature.
Once a further 6 minutes have elapsed, the EXV is then controlled according to suction superheat, discharge
temperature and compressor speed.
When the outdoor unit is in standby:
The EXV is at position 304 (steps).
When the outdoor unit stops:
The EXV first closes fully, then moves to the standby position (304 (steps)).
4.6
Outdoor Fan Control
The speed of the outdoor unit fan(s) is adjusted in steps, as shown in Table 3-5.3.
Table 3-5.3: Outdoor fan speed steps
Fan speed index
Fan speed (rpm)
5kW 7kW
10-16kW (1Ph)
12-16kW (3Ph)
Upper fan
1
Lower fan
2
Upper fan
1
Lower fan
2
0
0
0
0
0
0
0
1
300
300
300
-
300
-
2
340
340
330
300
330
300
3
400
400
400
380
400
380
4
450
450
460
440
460
440
5
520
520
520
500
520
500
6
600
600
630
610
630
610
7
680
680
780
760
780
760
8
730
730
-
-
-
-
9
800
800
-
-
-
-
Notes:
1.
The upper fan is labelled FAN_UP in the wiring diagram. Refer to the
Wellea
Mono
Engineering Data Book Part 2, 4 “Wiring diagram”.
2.
The lower fan is labelled FAN_DOWN in the wiring diagram. Refer to the
Wellea
Mono
Engineering Data Book Part 2, 4 “Wiring diagram”.
