Midea MV6-252WV2GN1 - 4 Startup Control; 4.1 Compressor Startup Delay Control; 4.2 Startup Control for Cooling Operation

V6 VRF 50/60Hz
36
Midea V6 Series Service Manual
4 Startup Control
4.1 Compressor Startup Delay Control
In initial startup control, compressor startup is delayed for 12 minutes in order to let the master unit search for the indoor
units’ addresses. In restart control (except in oil return operation and defrosting operation), compressor startup is delayed
such that a minimum of 7 minutes has elapsed since the compressor stopped, in order to prevent frequent compressor
on/off and to equalize the pressure within the refrigerant system.
4.2 Startup Control for Cooling Operation
Table 3-4.1: Component control during startup in cooling mode
Component
Wiring
diagram
label
8-12HP 14-16HP 18-28HP 30-32HP Control functions and states
Inverter compressor A
COMP(A)
● ● ● ●
Controlled according to load requirement, operating
frequency increased by 1 step / sec
Inverter compressor B
COMP(B)
● ●
DC fan motor A
FANA
● ● ● ● Fan speed
1
controlled according to discharge
pressure (P
c
):
 At initial speed for 90 seconds.
 Subsequently, P
c
checked every 10 seconds:
 P
c
≥ 2.7MPa => 1 step increase.
 P
c
≤ 2.1MPa => 1 step decrease.
DC fan motor B FANB ● ●
Electronic expansion valve
A
EXVA ● ● ● ●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to discharge temperature
Electronic expansion valve
B
EXVB ● ● ●
Electronic expansion valve
C
EXVC
● ● ● ●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to temperature different
between plate heat exchanger inlet and outlet
Four-way valve
ST1
● ● ● ●
Off
S
olenoid valve (oil
balance)
SV4 ● ● ● ● Closed for 200 secs, open for 600 secs, then closed
Solenoid valve (fast
defrosting (in heating) and
unloading (in cooling))
SV5 ● ● ● ● Open for 4 mins, then closed
S
olenoid valve (EXV
bypass)
SV6 ● ● ● ●
Open for 10 mins, then
controlled according to
pressure
Solenoid valve (indoor
units bypass)
SV7 ● ● Controlled according to load requirement
Solenoid valve (inverter
c
ompressor A vapor
injection)
SV8A ● ● ● ● Controlled according to inverter compressor A
Solenoid valve (inverter
compressor B vapor
injection)
SV8B ● ● Controlled according to inverter compressor B
Solenoid valve (inverter
compressor B pressure
balance)
SV9 ● ● Open before compressor B startup
Notes:
1. Refer to Table 3-5.3 in Part 3, 5.6 “Outdoor Fan Control” for more information on fan speed steps.