Midea V6 Series Service Manual page 49

V6 VRF 50Hz
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
Component
Inverter compressor A
Inverter compressor B
DC fan motor A
DC fan motor B
Electronic expansion valve A
Electronic expansion valve B
Electronic expansion valve C
Four-way valve
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)
48
Wiring diagram
8-12HP
label
COMP(A)
●
COMP(B)
FANA
●
FANB
EXVA
●
EXVB
EXVC
●
ST1
●
SV4
●
SV5
●
SV6
●
SV7
SV8A
●
SV8B
SV9
Table 3-7.6: Indoor unit component control during defrosting operation
Component
Thermo on
Fan
Thermo off
Thermo on
Electronic expansion valve
Thermo off
14-16HP 18-28HP 30-32HP
● ●
●
● ●
●
● ●
● ●
● ●
● ●
● ●
● ●
● ●
●
● ●
●
●
Unit state Control functions and states
Off
Standby Off
Off
480 (steps)
Standby 480 (steps)
480 (steps)
Control functions and states
●
Fixed frequency
●
●
Off
●
●
Position 480 (steps)
●
Position 480 (steps)
●
Off
●
Normal control
●
On
●
On
●
Normal control
●
Off
●
Off
●
Open before compressor B startup
●