Midea MV5-X252W/V2GN1 - 7.3 Defrosting Operation

V5 X VRF 50/60Hz
34 201608
Midea V5 X 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.
Table 3-7.5: Outdoor unit component control during defrosting operation
Component
Wiring diagram label
8-12HP
14-22HP
Control functions and states
Inverter compressor A
COMP(INV)
●
●
Controlled according to load requirement
Inverter compressor B
COMP(INV1)
●
DC fan motor A
FANA
●
●
Off
DC fan motor B
FANB
●
Electronic expansion valve A
EXVA
●
●
Fully open
Electronic expansion valve B
EXVB
●
Four way valve
ST1
●
●
Off
Solenoid valve (liquid refrigerant injection)
SV2
●
●
Normal control
Solenoid valve (oil balance)
SV4
●
●
Normal control
Solenoid valve (fast defrosting)
SV5
●
●
On
Solenoid valve (EXV bypass)
SV6
●
●
On
Solenoid valve (indoor units bypass)
SV7
●
●
Normal control
Table 3-7.6: Indoor unit component control during defrosting operation
Component
Unit state
Control functions and states
Fan
Thermo on
Off
Standby
Off
Thermo off
Off
Electronic expansion valve
Thermo on
480 (steps)
Standby
480 (steps)
Thermo off
480 (steps)