77
U2
U7
U1
U8
Ud
UF
UP
UH
U6
U3
U4
U5
U9
P1
P2
P9
P4
P5
P6
P8
Indication
Error
Error
code
w
1
Outdoor controller board
Contents
Inspection method
LED1 (Green) LED2 (Red)
3 blinking 1 blinking
2 blinking
3 blinking
W
1 Error code displayed on remote controller
W
2 Refer to service manual for indoor unit.
4 blinking
5 blinking
6 blinking
7 blinking
1 blinking
2 blinking
3 blinking
4 blinking
4 blinking
Abnormality of shell thermostat
and discharging temperature (TH4)
Abnormality of super heat due
to low discharge temperature
1
Check if stop valves are open.
2
Check if connectors (TH4, LEV-A, and LEV-B) on outdoor controller
board are not disconnected.
3
Check if unit fills with specified amount of refrigerant.
4
Measure resistance values among terminals on indoor valve and
outdoor linear expansion valve using a tester.
Abnormal high pressure (High
pressure switch 63H worked.)
Abnormality of outdoor fan
motor rotational speed
1
Check if indoor/outdoor units have a short cycle on their air ducts.
2
Check if connector (63H) on outdoor controller board is not disconnected.
3
Check if heat exchanger and filter is not dirty.
4
Measure resistance values among terminals on linear expansion valve
using a tester.
1
Check if stop valves are open.
2
Check looseness, disconnection, and converse connection of
compressor wiring.
3
Measure resistance values among terminals on compressor using a tester.
4
Check if outdoor unit has a short cycle on its air duct.
Compressor over current
breaking(Start-up locked)
Compressor over current breaking
Abnormality of current sensor (P.B.)
Abnormality of power module
Open/short of discharge thermistor (TH4)
Open/short of outdoor thermistors
(TH3, TH6, TH7 and TH8)
1
Check if connectors(TH3,TH4,TH6 and TH7)on outdoor controller board
and connector (CN3) on outdoor power board are not disconnected.
2
Measure resistance value of outdoor thermistors.
Abnormality of radiator panel
temperature
1
Check if indoor/outdoor units have a short cycle on their air ducts.
2
Measure resistance value of outdoor thermistor(TH8).
1
Check the outdoor fan motor.
2
Check if connector (TH3) on outdoor controller board is disconnected.
Abnormality of voltage
1
Check looseness, disconnection, and converse connection of
compressor wiring.
2
Measure resistance value among terminals on compressor using a tester.
3
Check the continuity of contactor (52C).
4
Check if power supply voltage decreases.
5
Check the wiring of CN52C.
6
Check the wiring of CNAF.
Abnormality of room temperature thermistor (TH1)
Abnormality of pipe temperature thermistor /Liquid (TH2)
Abnormality of pipe temperature
thermistor/Condenser-Evaporator
1
Check if connectors (CN20, CN21 and CN29) on indoor controller
board are not disconnected.
2
Measure resistance value of indoor thermistors.
Abnormality of drain sensor (DS)
Indoor drain overflow protection
1
Check if connector (CN31) on indoor controller board is not disconnected.
2
Measure resistance value of indoor thermistors.
3
Measure resistance value among terminals on drain-up machine using
a tester.
4
Check if drain-up machine works.
5
Check drain function.
Freezing (cooling)/overheating
(heating) protection
1
Check if indoor unit has a short cycle on its air duct.
2
Check if heat exchanger and filter is not dirty.
3
Measure resistance value on indoor and outdoor fan motors.
4
Check if the inside of refrigerant piping is not clogged.
Abnormality of pipe
temperature
1
Check if indoor thermistors(TH2 and TH5)are not disconnected from holder.
2
Check if stop valve is open.
3
Check converse connection of extension pipe. (on plural units connection)
4
Check if indoor/outdoor connecting wire is connected correctly.
(on plural units connection)
P.38
P.40
P.38
P.40
P.40
P.41
P.41
P.39
P.39
P.39
P.39
P.40
W
2
W
2
W
2
W
2
W
2
W
2
Detailed
reference
page
Protection from overheat operation(TH3)
OC374A--3.qxp 06.7.26 5:56 PM Page 77
