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VRF 50/60Hz
7.2 Defrosting Operation
In order to recover hea ng capacity, the defrosting opera on is conducted when the outdoor unit heat exchanger is
performing as an evaporator. The defros ng opera on is controlled according to outdoor ambient temperature, outdoor
heat exchanger temperature, indoor heat exchanger temperature and outdoor unit running me. When the outdoor unit is
running in defros ng, the digital display on outdoor main PCB will display "df".
Table 3-7.5: Outdoor unit component control during defrosting operation
Component
Inverter compressor
DC fan motor
Electronic expansion valve
Four-way valve
Table 3-7.6: Indoor unit component control during defrosting operation
Electronic expansion valve
Note： Prevent cold wind： It's only valid in hea ng opera on, and this control is priority to other controls (including hea ng oil return and defrost),
Which determine the conversion between se ng fan speed with low fan speed and turn off the fan according to the evaporator coil temperature
T2.
26
Wiring diagram
label
COMP
FAN
EEV1
ST1
Component
Unit state
Thermo on
Fan
Standby
Thermo off
Thermo on
Standby
Thermo off
28-56
Control functions and states
model
•
Fixed frequency
Fan speed controlled according to outdoor ambient
•
temperature (T4) before running in defros ng
•
Posi on 480 (steps)
•
Off
Control functions and states
Operate on se ng fan speed (Prevent cold wind priority)
Operate on se ng fan speed (Prevent cold wind priority)
Off
480 (steps)
480 (steps)
480 (steps)
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