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Check Code
Abnormal point and detection method
Open/short of outdoor unit thermistors
(TH3, TH32, TH33, TH6, TH7, and TH8)
Abnormal if open or short is detected
during compressor operation.
Open detection of thermistors TH3, TH32
and TH6 is not detected for 10 seconds to
10 minutes after compressor starting and
10 minutes after and during defrosting.
Note:
Check which unit has abnormality in
its thermistor by switching the mode of
SW2. (Refer to "8-7.OUTDOOR UNIT
OPERATION MONITOR FUNCTION".)
Heat sink thermistor (TH8) is in the power
U4
module.
Symbol
TH3
TH32
TH33
TH6
TH7
TH8
Temperature of heat sink
Abnormal if heat sink thermistor (TH8)
detects 94°C.
U5
Power module
Check abnormality by driving power module
in case overcurrent is detected.
(UF or UP error condition)
U6
Too low superheat due to low discharge
temperature
Abnormal if discharge superheat is
continuously detected −15: or less for
3 minutes even though linear expansion
U7
valve has minimum open pulse after
compressor starts operating for 10
minutes.
Outdoor fan motor
Abnormal if rotational frequency of the fan
motor is not detected during DC fan motor
operation.
Fan motor rotational frequency is abnormal if;
U8
• 100 rpm or below detected continuously
for 15 seconds at 20: or more outside
air temperature
• 50 rpm or below or 1500 rpm or more
detected continuously for 1 minute.
OCH562D
1 Disconnection or contact fail-
(
2 Defective thermistor
3 Defective outdoor controller
Thermistors
Name
Thermistor <Liquid temperature>
Thermistor <Inlet water temperature>
Thermistor <Suction pipe temperature>
Thermistor <Plate HEX liquid temperature>
Thermistor <Ambient temperature>
Internal thermistor
1 The outdoor fan motor is locked.
2 Failure of outdoor fan motor
3 Airflow path is clogged.
4 Ambient temperature is high.
5 Defective thermistor
6 Defective input circuit of
7 Failure of outdoor fan drive
1 Defective outdoor power cir-
2 Decrease of power supply voltage
3 Loosens, disconnection or
4 Defective compressor
1 Disconnection or loose
2 Defective holder of discharge
3 Disconnection or loose connection
4 Disconnection or loose
5 Defective linear expansion valve
1 Failure in the operation of the
2 Failure in the outdoor circuit
Cause
ure of connectors
)
Outdoor controller circuit board:
TH3, TH32, TH33, TH6/TH7
Outdoor power circuit board:
CN3
circuit board
outdoor power circuit board
circuit
cuit board
reverse of compressor wiring
connection
connection of discharge
temperature thermistor (TH4)
temperature thermistor
of linear expansion valve's coil
connection of linear expansion
valve's connector
DC fan motor
controller board
20
Judgment and action
1 Check connection of connector (TH3, TH32,
TH33, TH6/TH7) on the outdoor controller circuit
board. Check connection of connector (CN3) on
the outdoor power circuit board. Check the lead
wire for thermistor (TH3, TH32, TH33, TH6, TH7,
TH8). Refer to "8-6. TEST POINT DIAGRAM".
2 Check resistance value of thermistor (TH3, TH32,
TH33, TH6, TH7, TH8) or check temperature on
LED display.
(Thermistor/TH3, TH32, TH33, TH6, TH7,
TH8: Refer to "8-5.HOW TO CHECK THE
COMPONENTS.")
(SW2: Refer to "8-7.OUTDOOR UNIT
OPERATION MONITOR FUNCTION".)
3 Replace outdoor controller circuit board.
Open detection
Short detection
−40°C or below
90°C or above
−40°C or below
102°C or above
−40°C or below
90°C or above
−40°C or below
90°C or above
−40°C or below
90°C or above
−35°C or below
170°C or above
12 Check outdoor fan.
3 Check airflow path for cooling.
4 Check if there is something which causes
temperature rise around outdoor unit.
(Upper limit of ambient temperature is 46:.)
Turn off power, and on again to check if U5
is displayed within 30 minutes. If U4 is dis-
played instead of U5, refer to check code U4.
5 Check resistance value of thermistor (TH8)
or temperature by microcomputer.
(Thermistor/TH8: Refer to "8-5.HOW TO CHECK THE
COMPONENTS".) (SW2: Refer to "8-7.OUTDOOR
UNIT OPERATION MONITOR FUNCTION".)
6 Replace outdoor power circuit board.
7 Replace outdoor controller circuit board.
1 Replace outdoor power circuit board.
2 Check facility of power supply.
V
W phase) to
3 Correct the wiring (U
•
•
compressor. Refer to "8-6. TEST POINT
DIAGRAM (Outdoor power circuit board)".
4 Check compressor referring to "8-4.HOW TO
CHECK THE PARTS".
12 Check the installation conditions of dis-
charge temperature thermistor (TH4).
3 Check the coil of linear expansion valve.
Refer to "8-5.HOW TO CHECK THE
COMPONENTS".
4 Check the connection or contact of LEV-A
and LEV-B on outdoor controller circuit board.
5 Check linear expansion valve.
Refer to "8-4.HOW TO CHECK THE PARTS".
1 Check or replace the DC fan motor.
2 Check the voltage of the outdoor circuit
controller board during operation.
3 Replace the outdoor circuit controller board.
(When the failure is still indicated even after
performing the remedy 1 above.)
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