[3-3 Functions of the Major Components of Outdoor Unit ]
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HWE12050 GB
3 Major Components, Their Functions and Refrigerant Circuits
Sole-
noid
valve
SV1a
Discharge-
suction
bypass
1) High/low pressure bypass at
start-up and stopping, and
capacity control during low-
load operation
2) High-pressure-rise preven-
tion
AC220-240V
Open while being powered/
closed while not being pow-
ered
Continuity check
with a tester
SV5b
Heat
exchanger
capacity con-
trol
Controls outdoor unit heat ex-
changer capacity
AC220-240V
Closed while being powered/
open while not being powered
SV5c EP300 -
EP450
models
only
SV9 High-pressure-rise prevention Open while being powered/
closed while not being pow-
ered
SV2 High-Low pressure bypass during
defrost
Open while being powered/
closed while not being pow-
ered
Linear
expan-
sion
valve
LEV1
(SC control)
Adjusts the amount of bypass flow
from the liquid pipe on the outdoor
unit during cooling
DC12V
Opening of a valve driven by a
stepping motor 0-480 pulses
(direct driven type)
Same as indoor
LEV
The resistance val-
ue differs from that
of the indoor LEV.
Refer to the follow-
ing page(s). [8-8
Troubleshooting
LEV Prob-
lems](page 228)
LEV2
(Refrigerant
flow adjust-
ment)
Adjusts refrigerant flow during
heating
DC12V
Opening of a valve driven by a
stepping motor 2100 pulses
(Max. 3000 pulses)
Refer to the section
"Continuity Test
with a Tester".
Continuity between
white and orange.
Continuity between
yellow, brown, and
blue.
4-way
valve
21S4a Changeover between heating and
cooling
AC220-240V
Dead: cooling cycle
Live: heating cycle
Continuity check
with a tester
21S4b 1) Changeover between heating
and cooling
2) Controls outdoor unit heat ex-
changer capacity
AC220-240V
Dead: cooling cycle
Outdoor unit heat exchanger
capacity at 100%
Live: heating cycle
Outdoor unit heat exchanger
capacity at 50%
or heating cycle
21S4c EP300-
EP450
models
only
Fan
motor
FAN motor
1,2
FAN mo-
tor 2 is
only on
the
EP350 -
EP450
models.
Regulates the heat exchanger ca-
pacity by adjusting the operating
frequency and operating the pro-
peller fan based on the operating
pressure.
AC380-400V, 920W
Part
name
Symbols
(functions)
Notes Usage Specifications Check method
Yellow
White
Orange
Brown Blue
M
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