V6 VRF 50Hz
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Midea V6 Series Service Manual
7.3 Defrosting Operation
In order to recover heating capacity, the defrosting operation is conducted when the outdoor unit heat exchanger is
performing as an evaporator. The defrosting operation is controlled according to outdoor ambient temperature, outdoor
heat exchanger temperature, indoor heat exchanger temperature and outdoor units running time. When the outdoor unit
is running in defrosting, the digital display on outdoor main PCB will display “df”.
Table 3-7.5: Outdoor unit component control during defrosting operation
Control functions and states
Electronic expansion valve A
Electronic expansion valve B
Electronic expansion valve C
Solenoid valve (oil balance)
Solenoid valve (fast defrosting (in
heating) and unloading (in cooling))
Solenoid valve (EXV bypass)
Solenoid valve (indoor units bypass)
Solenoid valve (inverter compressor
A vapor injection)
Solenoid valve (inverter compressor
B vapor injection)
Solenoid valve (inverter compressor
B pressure balance)
Open before compressor B startup
Table 3-7.6: Indoor unit component control during defrosting operation
Control functions and states
Electronic expansion valve