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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 outdoor 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
Inverter compressor A
COMP(A)
Inverter compressor B
COMP(B)
DC fan motor A
DC fan motor B
Electronic
expansion
valve A
Electronic
expansion
valve C
Four-way valve
Solenoid valve (liquid
refrigerant injection)
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)
Notes:
1.
Refer to Table 3-5.3 in Part 3, 5.6 "Outdoor Fan Control" for more information on fan speed steps.
Wiring
diagram
8-12HP
14-18HP
label
●
●
FANA
●
●
FANB
EXVA
●
●
EXVC
●
●
ST1
●
●
SV2
SV4
●
●
SV5
●
●
SV6
●
●
SV7
●
SV8A
●
●
SV8B
SV9
20-24HP
26-28HP
30-32HP
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
42
Control functions and states
Controlled according to load requirement,
operating frequency increased by 1 step / sec
Fan speed
controlled according to discharge
1
pressure (P
):
c
At initial speed for 90 seconds.
Subsequently, P
checked every 10
c
seconds:
P
≥ 2.7MPa => 1 step increase.
c
P
≤ 2.1MPa => 1 step decrease.
c
Position (steps) from 0 (fully closed) to 480 or
3000 (fully open), controlled according to
discharge temperature
Position (steps) from 0 (fully closed) to 480
(fully
open),
controlled
temperature different between plate heat
exchanger inlet and outlet
Off
Off
Closed for 200 secs, open for 600 secs, then
closed
Open for 4 mins, then closed
Open for 10 mins, then controlled according
to pressure
Controlled according to load requirement
Controlled according to inverter compressor
A
Controlled according to inverter compressor
B
Open before compressor B startup
according
to
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