71
OCH738
Indication
Error
Outdoor controller board
Contents
Check
code
*1
Inspection method
Detailed
reference
page
LED1
(Green)
LED2
(Red)
3 blinking
1 blinking
Abnormality of discharge thermistor/comp.
surface thermistor (TH4/TH33)
U2
1
Check if stop valves are open.
2
Check if connectors (TH4,TH33, LEV-A, LEV-B)
on outdoor controller board are not disconnected.
3
Check if unit is filled with specified amount of
refrigerant.
4
Measure resistance values among terminals on
indoor valve and outdoor linear expansion valve
using a tester.
P.37
Abnormality of superheat due to low
discharge temperature
U7
P.38
2 blinking
Abnormal high pressure(63H operated)/High
compressor temperature (TRS operated)
U1
1
Check if indoor/outdoor units have a short cycle
on their air ducts.
2
Check if connector (63H and TRS) 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.
5
Check if stop valves are open.
6
Check if unit is filled with specified amount of
refrigerant.
P.37
3 blinking
Abnormality of outdoor fan motor rotational
speed
U8
1
Check the outdoor fan motor.
2
Check if connector (TH3) on outdoor controller
board is disconnected.
P.38
Protection from overheat operation(TH3)
Ud
P.40
4 blinking
Compressor overcurrent breaking(Startup
locked)
UF
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.
P.40
Compressor overcurrent breaking
UP
P.40
Abnormality of current sensor (P.B.)
UH
P.40
Abnormality of power module
U6
P.38
5 blinking
Open/short of discharge thermistor (TH4)
and comp. surface thermistor (TH33)
U3
1
Check if connectors(TH3,TH4,TH6,TH7
and TH33) on outdoor controller board and
connector (CN3) on outdoor power board are not
disconnected.
2
Measure resistance value of outdoor thermistors.
P.37
Open/short of outdoor thermistors
(TH3, TH6, TH7 and TH8)
U4
P.38
6 blinking
Abnormality of heat sink
temperature
U5
1
Check if indoor/outdoor units have a short cycle
on their air ducts.
2
Measure resistance value of outdoor
thermistor(TH8).
P.38
7 blinking
Abnormality of voltage
U9
1
Check looseness, disconnection, and converse
connection of compressor wiring.
2
Measure resistance value among terminals on
compressor using a tester.
3
Check if power supply voltage decreases.
4
Check the wiring of CN52C.
P.39
4 blinking
1 blinking
Abnormality of room temperature thermistor (TH1)
P1
1
Check if connectors (CN20, CN21, CN29
and CN44) on indoor controller board are not
disconnected.
2
Measure resistance value of indoor thermistors.
*2
Abnormality of pipe temperature thermistor /
Liquid (TH2)
P2
*2
Abnormality of pipe temperature thermistor/
Condenser-Evaporator
P9
*2
2 blinking
Abnormality of drain sensor (DS)
Float switch(FS) connector open
P4
1
Check if connector (CN31)(CN4F) on indoor
controller board is not disconnected.
2
Measure resistance value of indoor thermistors.
3
Measure resistance value among terminals on
drain pump using a tester.
4
Check if drain pump works.
5
Check drain function.
*2
Indoor drain overflow protection
P5
Leakage error (refrigerant system)
PA
1
Converse connection of piping or wiring
Note: The error will be cancelled by turning off
power, and on again.
2
Check if there are any inclination or clogging in
drain pipe.
3
Check if drain pan or drain sensor is dirty.
4
Check if any foreign matter is attached to the
moving part of float switch.
5
Check LEV for proper function.
*2
3 blinking
Freezing (cooling)/overheating
(heating) protection
P6
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.
*2
4 blinking
Abnormality of pipe
temperature
P8
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)
*2
5 blinking
Indoor unit fan motor error
PB(Pb) Defective fan motor winding
*2
*1 Check code displayed on remote controller
*2 Refer to the indoor unit’s service manual.