Mitsubishi Electric SUZ-KA24NAHZ Service Manual page 64

Indication
Outdoor controller
board
LED1 LED2
(Green) (Red)
3 blinking 1 blinking Abnormality of Discharge
temperature (TH4) and Comp.
surface temperature (TH33)
Abnormality of superheat due to
low discharge temperature
2 blinking Abnormal high pressure (High
pressure switch 63H worked.)
Abnormal low pressure (Low
pressure switch 63L worked.)
3 blinking Abnormality of outdoor fan motor
rotational speed
Protection from overheat
operation(TH3)(T
4 blinking Compressor overcurrent breaking
(Startup locked)
Compressor overcurrent breaking
Abnormality of current sensor
(P.B.)
Abnormality of power module
5 blinking Open/short of discharge
thermistors (TH4) (TH33)
Open/short of outdoor thermistors
(TH3, TH32, TH6, TH7 and TH8)
6 blinking Abnormality of heatsink
temperature
7 blinking Abnormality of voltage
4 blinking 1 blinking Abnormality of room temperature
thermistor (TH1)
Abnormality of pipe temperature
thermistor /Liquid (TH2)
Abnormality of pipe temperature
thermistor/Condenser-Evaporator
2 blinking Abnormality of drain sensor (DS)
Float switch connector open (FS)
Indoor drain overflow protection
3 blinking Freezing (cooling)/overheating
(heating) protection
4 blinking Abnormality of pipe temperature
*Check code displayed on remote controller
**Refer to service manual for indoor unit.
OCH754A
Check
Contents
code*
1
U2
2
3
U7
4
1
U1
2
3
UL
4
1
U8
2
Ud
)
63HS
1
UF
2
UP
3
UH
U6
4
1
U3
U4
2
1
U5
2
1
U9
2
3
1
P1
2
P2
P9
1
P4
2
3
P5
4
5 Check drain function.
1
2
P6
3
4
1
2
P8
3
4
Error
Inspection method
Check if stop valves are open.
Check if connectors (TH4, TH33, LEV-A, and LEV-B) on outdoor
controller board are not disconnected.
Check if unit is filled with specified amount of refrigerant.
Measure resistance values among terminals on indoor valve and
outdoor linear expansion valve using a tester.
Check if indoor/outdoor units have a short cycle on their air ducts.
Check if connector (63H) (63L) on outdoor controller board is not
disconnected.
Check if heat exchanger and filter is not dirty.
Measure resistance values among terminals on linear expansion
valve using a tester.
Check the outdoor fan motor.
Check if connector (TH3) (T
63HS
disconnected.
Check if stop valves are open.
Check looseness, disconnection, and converse connection of
compressor wiring.
Measure resistance values among terminals on compressor using a
tester.
Check if outdoor unit has a short cycle on its air duct.
Check if connectors (TH3,TH32,TH33,TH4, and TH7/6) on outdoor
controller board and connector (CN6) on outdoor power board are
not disconnected.
Measure resistance value of outdoor thermistors.
Check if indoor/outdoor units have a short cycle on their air ducts.
Measure resistance value of outdoor thermistor (TH8).
Check looseness, disconnection, and converse connection of
compressor wiring.
Measure resistance value among terminals on compressor using a
tester.
Check if power supply voltage decreases.
Check if connectors (CN20, CN21, CN29 and CN44) on indoor
controller board are not disconnected.
Measure resistance value of indoor thermistors.
Check if connector (CN31)(CN4F) on indoor controller board is not
disconnected.
Measure resistance value of indoor thermistors.
Measure resistance value among terminals on drain-up machine
using a tester.
Check if drain-up machine works.
Check if indoor unit has a short cycle on its air duct.
Check if heat exchanger and filter is not dirty.
Measure resistance value on indoor and outdoor fan motors.
Check if the inside of refrigerant piping is not clogged.
Check if indoor thermistors(TH2 and TH5) are not disconnected
from holder.
Check if stop valve is open.
Check converse connection of extension pipe. (on plural units
connection)
Check if indoor/outdoor connecting wire is connected correctly.(on
plural units connection)
64
) on outdoor controller board is
Detailed
reference
page
P.28
P.30
P.28
P.32
P.30
P.31
P.31
P.32
P.31
P.29
P.29
P.29
P.29
P.30
**
**
**
**
**
**
**