Midea MV6-252WV2GN1 Service Manual page 38

4.3 Startup Control for Heating Operation
Table 3-4.2: Component control during startup in heating mode
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)
Wiring
diagram 8-12HP 14-16HP
label
COMP(A)
● ●
COMP(B)
FANA
● ●
FANB
EXVA
● ●
EXVB
●
EXVC
● ●
ST1
● ●
SV4
● ●
SV5
● ●
SV6
● ●
SV7
●
SV8A
● ●
SV8B
SV9
18-28HP 30-32HP
Controlled
● ●
operating frequency increased by 1 step / sec
● ●
Open once the four-way valve has opened,
● ●
controlled
● ●
temperature and load requirement
Position (steps) from 0 (fully closed) to 480 (fully
● ●
open), controlled according to discharge superheat
● ●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to temperature
● ●
different between plate heat exchanger inlet and
outlet
On
● ●
Closed for 200 secs, open for 600 secs, then closed
● ●
Open for 4 mins, then closed
● ●
Off
● ●
Controlled according to load requirement
●
Controlled according to inverter compressor A
● ●
Controlled according to inverter compressor B
● ●
Open before compressor B startup
● ●
V6 VRF 50/60Hz
Control functions and states
according to load requirement,
according to outdoor ambient
37