McQuay 4AC20C / M4AC020C, Installation Manual

Page: 28 / 125

1-15
Figure 9
4AC/AC40/50/60 C/CR
Remove this wire
when doing
wiring for fan
speed controller
Wiring for fan
speed controller
(FSC)
FSC
OF IN OF OUT
TB3
TB3
OF IN OF OUT
TO (PCB)
OUT_FAN1
TO (A) OF_1
CAPACITOR
Power supply 400V / 3Ph-N / 50Hz
L1 N
TB1 R S T N
L2
L3
ISOLATOR SWITCH FIELD INSTALLATION
The isolator switch does not come as standard item with the units. It is advisable to have it field installed. The isolator switch must
be capable of making, carrying and breaking currents under normal circuit condition. It must be of AC23A duty and fully compliant
to IEC: 947-3.
For isolator switch selection, check the starting and running consumption specified in Table B. Be sure to connect a ground wire
from incoming power supply, either direct to the terminal box panel or use an auxiliary ground terminal in the isolator switch. To
install an isolator switch, wire it to the terminal block as shown in the two figures in page ix.
Operation of the mini chillers without any fan speed control is limited to an ambient temperature
of 17°C. With the fan speed control, the units are able to operate down to -5°C.
The fan speed controller
does not come as a standard item in the mini chiller units. It is field-
installed.
All mini chillers will have a 1/4" access valve provided for along the liquid line of the refrigerant
circuit. This valve is for direct pressure connection to the fan speed controller.
To install the fan speed controller, screw in the female adaptor to the 1/4" access valve. Use a
pair of spanners to tighten properly (max. torque 15 Nm). See Fig. 8. Ensure there is no leakage
at the joint.
Wire the fan speed controller to the terminal blocks. See Fig. 9.
FAN SPEED CONTROLLER (OPTIONAL)
TB3
Power supply 230V / 1Ph-N / 50Hz
Remove this wire
when doing wiring
for fan speed
controller
Figure 8
OF IN OF OUT
OF IN OF OUT
Wiring for fan
speed controller
(FSC)
FSC
TB3
TO (PCB)
OUT_FAN1
TO (A) OF
CAPACITOR
L1 N
TB1 L/L1 N/L2
4AC/AC20/25/30 C/CR
15 Nm